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Hydrogen production from renewable sources is gaining increasing importance for application as fuel, in particular with high efficiency and low impact devices such as fuel cells. In addition, the possibility to produce more sustainable hydrogen for industrial application is also of interest for fundamental industrial processes, such as ammonia and methanol synthesis. Catalytic processes are used in most options for the production of hydrogen from renewable sources. Catalysts are directly involved in the main transformation, as in the case of reforming and of electro-/photo-catalytic water splitting, or in the upgrade and refining of the main reaction products, as in the case of tar reforming. In every case, for the main processes that reached a sufficiently mature development stage, attempts of process design, economic and environmental impact assessment are presented, on one hand to finalise the demonstration of the technology, on the other hand to highlight the challenges and bottlenecks. Selected examples are described, highlighting whenever possible the role of catalysis and the open issues, e.g. for the H2 production from reforming, aqueous phase reforming, biomass pyrolysis and gasification, photo- and electro-catalytic processes, enzymatic catalysis. The case history of hydrogen production from bioethanol for use in fuel cells is detailed from the point of view of process design and techno-economic validation. Examples of steady state or dynamic simulation of a centralised or distributed H2 production unit are presented to demonstrate the feasibility of this technology, that appears as one of the nearest to market. The economic feasibility seems demonstrated when producing hydrogen starting from diluted bioethanol. [ABSTRACT FROM AUTHOR]

It is generally accepted that the world's reliance on fossil fuels had negative implications, such as a decline in crude oil supply, a drop in air quality, an increase in global temperature, unpredictable weather change, etc. Biofuel production is one of the best options for minimizing the quantity of conventional fuel used. This article presents theoretical and practical methods for process improvement, as well as a brief review of the characteristics of bioethanol production and limitations by using various pre-treatment techniques with wastes such as fruit and lignocellulose biomass to ethanol production using various microbe species. Bioethanol has a variety of applications, including petrol blending, solvent use, and distillery sectors. The pH (4–4.3), temperature (32 °C), and kind of microorganisms all have a significant impact on bioethanol production. Many significant phenolic chemicals and bioactive substances have been extracted from waste during bioethanol manufacturing. The approaches discussed in this study, such as pre-treatment, extraction, and distillation, can enhance the yield of bio-ethanol, which can be beneficial in many ways in the future. [ABSTRACT FROM AUTHOR]

The current study describes the fabrication of nano-catalyst by embedding the magnetic nanoparticles as a core in silica shell to obtain the structure of Fe3O4@SiO2 and then functionalized with sulfonyl groups. The intrinsic properties of nano-catalysts were scrutinized for morphological, crystal structure, elemental and chemical bonding analysis using SEM, XRD, EDS and FT-IR, respectively. The acid density and saturation magnetization were observed to be 0.20 mmol g−1 and 56 emu g−1, respectively. In this study, banana peel waste was pre-treated and hydrolyzed into total reducing the sugar by sulfonated silica magnetic catalyst. A single-factor optimization method has also been used to investigate the influence of catalyst/solid quantity, reaction temperature and time on reducing sugar. The optimum sugar-reducing yield of about 73% was achieved with 0.3% (w/v) of catalyst loading at 140 °C for 2 h. In addition, the spent sulfonated silica catalyst was regenerated and reused up to 3 times. The fermentation by Saccharomyces cerevisiae was conducted with banana peel hydrolysate, and fermentation efficiency reached 83% after 48 h. [ABSTRACT FROM AUTHOR]

In cassava ethanol studies, few studies have combined production data from plants with simulation models, and further investigated the environmental emissions caused by different production processes. In this paper, based on the survey data of cassava ethanol plants in Guangxi, we established an ethanol production process model and conducted a life cycle assessment of the raw meal fermentation (RMF) process and traditional clinker fermentation (CF) process. The impact of fermentation broth alcohol concentration on the environmental emissions of the whole process was also investigated based on the conventional CF process. The results showed that the RMF production process had more advantages than the CF production process in terms of energy savings, with 633 MJ per ton of ethanol and 37.39 kg eq/t ethanol of CO2 reduction. Increasing the alcohol concentration of the fermentation broth facilitated the removal of environmental emissions from the process. All cassava ethanol production models exhibited net energy ratios of no less than 2.74. Of these, the RMF 15% showed the most competitive net energy ratio of 2.97, the highest renewability of 4.52, and the lowest environmental emissions. A detailed analysis of the environmental impacts by the ethanol production phase showed that the distillation section was the critical point for energy saving and emission reduction. Sensitivity analysis showed that fertilizer and natural gas consumption could not be ignored. [ABSTRACT FROM AUTHOR]

This study investigates the potential for bioethanol production of six types of typical German leftover baked products: bread rolls, pretzel rolls, fine rye bread, white bread, pastry, and cream cakes. The experimental setup consisted of two experiments—one as a control and another with the addition of diammonium phosphate (DAP) to the mash. In terms of monosaccharide concentration at 30% dry matter (DM), white bread mash exhibited the highest level at 251.5 g/L, while cream cakes mash had the lowest at 186 g/L. The highest ethanol production occurred after 96 h of fermentation with rye bread, yielding 78.4 g/L. In contrast, despite having the highest monosaccharide levels, white bread produced only 21.5 g/L of ethanol after 96 h. The addition of DAP accelerated monosaccharide consumption in all baked products, with cream cakes completing the process in just 24 h. Bread rolls, pretzel rolls, pastry, and white bread fermentations finished within 72 h. Ethanol yields significantly increased in three DAP samples, with pretzel rolls yielding the highest ethanol concentration at 98.5 g/L, followed by white bread with 90.6 g/L, and bread rolls with 87.7 g/L. DAP had a substantial impact on all samples, reducing fermentation time and/or increasing ethanol yield. This effect was particularly pronounced with white bread, where it improved conversion efficiency from 17 to 72%, resulting in 90.6 g/L of ethanol. These results demonstrate that waste baked products hold substantial potential for bioethanol production, and this potential can be further enhanced through the addition of DAP. [ABSTRACT FROM AUTHOR]

The current study pertains performance optimization of multiple responses of a variable compression ratio diesel engine in regard to variation in load, compression ratio, and fuel type. A total of 9 number of experimental runs are performed as per the design of experiment suggested by Taguchi technique for three different load of 4 kg, 8 kg, and 12 kg, compression ratio of 14, 16, and 18, and fuel type of diesel, e-diesel (85% diesel and 15% bioethanol blend), and nano-fuel (85% diesel and 15% bioethanol blend with 25 ppm alumina nanoparticles). The bioethanol used in this study prepared from waste rice straw. The energy efficiency (η), exergy efficiency (ɛE), nitrogen oxide emission, and % relative cost variation are measured as output performances of this study. Fuel type has been identified as the most promising factor to energy efficiency, and exergy efficiency with a contribution of 41.1% and 64.53%, respectively. Load has been identified as the most promising factor to NOx emission, and % relative cost variation with a contribution of 71.69% and 34.92%, respectively. The compression ratio has been identified as the least contributing factor for all output performances. Nano-fuel attains higher sustainability index of 1.923 compared to other fuel due to lower depletion rate. Multiple output performance optimization has been carried out for maximum η, and ɛE, as well as minimum nitrogen oxide emission, and % relative cost using Taguchi–Grey technique. 19.37% enhancement in overall performance of the test engine is observed for determined optimal input parameters of 4 kg load, 18 compression ratio and nano-fuel. [ABSTRACT FROM AUTHOR]

Bioethanol production from agro-food industry waste is one of the suitable alternatives to fossil fuels. In this study, six agro-food wastes were evaluated to select those with a high concentration of starch or fermentable sugars for bioethanol processing. Yeast's ability to produce biofuels by fermentation is affected by temperature. In this study, thermotolerant yeasts, obtained from natural sources in Algeria (soil and agro-food waste), were selected for their capacity to produce and tolerate bioethanol. Three wastes were selected, two of which had significant starch content. In order to get fermentable sugars, these wastes underwent chemical and enzymatic hydrolysis. The selected yeasts were identified by morphological, physiological, biochemical, and molecular characterization. Enzymatic and acid hydrolysis of whole potato and durum wheat bran released (190 g/L and 130 g/L) and (138.40 g/L and 90.03 g/L) reducing sugars, respectively. Among the isolated strains, three were found to be able to produce bioethanol, namely Candida tropicalis, Candida glabrata, and Saccharomyces cerevisiae. These strains were identical to those stored in the data bank with 99%, 100%, and 100%, respectively. In addition, C. glabrata and C. tropicalis exhibited an ethanol tolerance of up to 14%, while S. cerevisiae tolerates up to 15%. Interestingly, enzymatic hydrolysis–treated potatoes produced a considerable amount of bioethanol after 48 h of fermentation by S. cerevisiae (7.525% (v/v)), C. glabrata (6.80% (v/v)), and C. tropicalis (4.50% (v/v)). Taken together, our findings suggest that S. cerevisiae and whole potato waste could be considered good candidates for industrial bioethanol production at high temperatures. [ABSTRACT FROM AUTHOR]

Purpose: Food waste is considered a potential source for biofuel production, with gaps in the processes that need to be addressed and a necessity to evaluate the environmental, economic, and social impacts of these processes comprehensively to assess their sustainability fully. The aim was to conduct a life cycle assessment (LCA) of bioethanol derived from banana, potato, and papaya waste across three process stages (pretreatment, enzymatic hydrolysis, and fermentation). Methods: The process was assessed in two additional stages: one considering energy consumption and the other excluding energy consumption of the equipment used, referred to as non-energy processes. This distinction was made because a laboratory-scale process was utilized, which does not accurately reflect energy costs on a large scale. The study employed Ecoinvent database 3.4 and the ReCiPe 2016 method (midpoint and endpoint) to evaluate impacts, along with Monte Carlo simulation in SimaPro 8.5.0.0 software for uncertainty analysis. Results: The LCA revealed that the fermentation stage accounted for the most significant number of impacts and environmental damages in all categories in the complete processes. In the non-energy processes, the pretreatment stage for waste from evaluated foods exhibited the highest impacts and damages. The most significant environmental impacts and damages across all scenarios were global warming potential (GWP) and resources, respectively. Conclusions: Banana waste has higher impact than potatoes and papaya. Optimizing processes, using renewable energy, sustainable pH adjustment, and enzyme reuse can enhance sustainability. No studies were found that conducted an LCA of bioethanol production from papaya waste. [ABSTRACT FROM AUTHOR]

The conversion of Eucalyptus biomass to ethanol via fermentation is beset with challenges including efficient sugar utilisation, the presence of inhibitors, expensive nutrients, and low yields. To address some of these challenges, this study evaluated Thermosacc Dry® and GSF335 xylose recombinant yeast in fermentations using acid pretreated Eucalyptus grandis fibre and hydrolysates. These fermentations were supplemented with novel and low-cost nutrients. Contrary to previous reports, the inclusion of trace metals in saccharification and hydrolysis fermentations of whole slurries did not eliminate the inhibitory effects of acetic acid. Elevated levels of xylitol and acetic acid suggested a redirection of carbon flux to redress redox imbalances in both yeast types. Using GSF335 propagated in xylose-enriched liquors, and Nutri-Plex Plus™, diammonium phosphate, or crude dried spent yeast as nitrogen sources, saccharification and hydrolysis fermentations produced ethanol yields ranging from 141.4 to 145.6 kg t−1 dry weight E.grandis. Inclusion of yeast hulls and trace metals in simultaneous saccharification and fermentations yielded 175.6 kg ethanol t−1 dry weight E.grandis, corresponding to a 64.4% conversion efficiency. Results from this study support the use of novel low-cost waste by-products as nutrient supplements in bioethanol production from Eucalyptus biomass. Furthermore, they have implications for the production of bioethanol from other lignocellulosic materials and warrant further investigation. [ABSTRACT FROM AUTHOR]

A novel pretreatment process based on prioritized microbes was developed to improve the yield of reducing sugars from red (Gracilaria corticata), brown (Sargassum wightii), and green (Ulva fasciata) seaweeds as a cheap, eco-friendly method for seaweed saccharification. Prioritization of six microbes from a collection of 24 microbes was initially done using a unique stepwise strategy considering different polysaccharides present in varied seaweed types. Final selection of three microbes was based on the release of reducing sugars from different seaweed groups in the saccharification process. The selected microbes significantly increased the release of reducing sugars compared to the control conditions in all three seaweed species, with significant differences (P<0.05) based on the media, microbes, seaweed species, processed condition, and days of hydrolysis. Factor analysis of mixed data indicated that microbes contributed to the maximum variability of the data. Vibrio parahaemolyticus caused the maximum biomass conversion ratio for reducing sugars from S. wightii (22.31 ± 0.65%) and U. fasciata (24.6 ± 1.28%) with an increment of 8.9% and 9.35%, respectively from control conditions. The maximum biomass conversion of G. corticata was 24.8 ± 0.51% following Bacillus amyloliquefaciens treatment with an increment of 6.39% from the control. Even though different combinations of three prioritized microbes produced better saccharification than the control conditions, individual use of prioritized microbes made a better release of reducing sugars. In brief, seaweed hydrolysis using the prioritized microbes of the present study can be applied to improve the saccharification process of seaweeds in an eco-friendly and less expensive platform. [ABSTRACT FROM AUTHOR]

In this study, the giant reed (Arundo donax L.) was used as a substrate for bioethanol production. To study and optimize the effect of bioethanol production parameters, including sodium hydroxide (NaOH) concentration (3–9, w/w%), temperature (60–180 °C), and pretreatment duration (30–120 min), on bioethanol concentration, and theoretical bioethanol yield, response surface methodology (RSM) based on the Box–Behnken design (BBD) was used. Alkaline pretreatment with NaOH was done on the substrate and all the samples were subjected to an enzymatic degradation experiment under conditions of loading 30 FPU cellulase/g dry biomass and then converted to bioethanol by Saccharomyces cerevisiae yeast. The results showed significant effects of the variables on bioethanol production, except for the effects of temperature on theoretical bioethanol yield. The optimal conditions for producing bioethanol under alkaline pretreatment conditions are a NaOH concentration of 3.0%, a temperature of 60 °C, and a pretreatment duration of 30 min which identified the optimal conditions of bioethanol concentration (3.19 g/L), and theoretical bioethanol yield (25.62%). These results contribute to supporting the potential of giant reed biomass as a suitable raw material for bioethanol production. [ABSTRACT FROM AUTHOR]

The pretreatment and saccharification of dewaxed bagasse (DWB) has been investigated under various reaction conditions ranging 2000 to 3200 psi, at 70 ± 1 °C in supercritical carbon dioxide (SCC). This has been in attempt to transform the DWB into fermentable sugar and bioethanol in high yields. The effect of SCC mediated pretreatment and enzymatic hydrolysis on structural and morphological alterations in DWB has been ascertained through diverse analytical methods. The sugar has been released through cellulase (40 FPU/mL) mediated enzymatic hydrolysis of pretreated DWB in sodium acetate buffer (pH 4.7) within 1 h at SCC 2800 psi, 70 ± 1 °C. The released sugar was subsequently fermented in the presence of yeast (Saccharomyces crevices, 135 CFU) at 28 ± 1 °C over 72 h to afford the bioethanol. The SCC mediated process conducted in acetic acid:water media (1:1) at 2800 psi, 70 ± 1 °C over 6 h has afforded the pretreated DWB with maximum yield towards the production of fermentable sugar and bioethanol. The production of fermentable sugar and bioethanol has been electrochemically estimated through cyclic voltammetry (CV) and square wave voltammetry (SWV) over glassy carbon electrode in KOH (0.1 M). The electrochemical methods were found selective and in close agreement for estimation of the yields (%) of fermentable sugars and bioethanol. The yield (%) of fermentable sugar estimated from CV and SWV were 80.10 ± 5.34 and 79.00 ± 5.09 respectively. Whereas the yield (%) of bioethanol estimated from CV and SWV were 81.30 ± 2.78% and 78.6 ± 1.25% respectively. Present investigation delivers a SCC mediated green and sustainable method of pretreatment of DWB to afford the enhanced saccharification, to produce bioethanol in high yields. [ABSTRACT FROM AUTHOR]

Nowadays, in the bioethanol production process, improving the simplicity and yield of cell wall saccharification procedure represent the main technical hurdles to overcome. This work evaluated the application of a rapid and cost-effective technology such as near -infrared spectroscopy (NIRS) for easily predict saccharification efficiency from corn stover biomass. Calibration process focussing on the number of samples and the genetic background of the maize inbred lines were tested; while Modified Partial Least Squares Regression (MPLS) and Multiple Linear Regression (MLR) were assessed in predictions. The predictive capacity of the NIRS models was mainly determined by the coefficient of determination (r2ev) and the index of prediction to deviation (RPDev) in external validation. Overall, we could check a better efficiency of the NIRS calibration process for saccharification using larger number of observations (1500 sample set) and genetic backgrounds; while MPLS regression provided better prediction statistics (r2ev = 0.80; RPDev = 2.21) compared to MLR (r2ev = 0.68; RPDev = 1.75). These results indicate that NIRS could be successfully implemented as a large-phenotyping tool in order to test the saccharification potential of corn biomass. Highlights: • NIRS could be successfully implemented as a large-phenotyping tool in order to test the saccharification potential of corn biomass. • NIRS wavelengths noted provide information about associated chemical components interfering in the saccharification potential. • The best efficiency in the NIRS calibration process was obtained using larger number of observations (1500 samples) and genetic backgrounds. • MPLS regression model is the most reliable for NIRS prediction of corn saccharification. [ABSTRACT FROM AUTHOR]

Bagasse and straw are the two feedstocks used to produce cellulosic ethanol from sugarcane. Although this technology is advancing commercially, the differentiation between bagasse and straw remains elusive. This work investigates bagasse and straw supply, conditioning, and pretreatment in a pilot-scale steam-explosion continuous reactor (~ 10 kg/h feed) to illuminate the critical feedstock differences for process scale-up. Evaluating biomass across four sequential harvest seasons (2018–2021) shows that straw supplied in bales requires extra conditioning to reduce mineral matter and particle size before feeding into the reactor. Moreover, straw composition is more variable and consistently has lower contents of glucan (35.6–38.8%) and carbohydrate potential (glucose + xylose, 649–704 kg/dry tonne) compared to bagasse (40.8–42.9%; 735–760 kg/dry tonne). Biomass pretreatments without (190 °C, 5–15 min) and with sulfuric acid catalyst (149–170 °C; 5–15 min; 0.5–5.12%, m/m) show that straw differs from bagasse by presenting a higher acid neutralization capacity and about 5% of labile glucans. These results suggest that straw crushing and aqueous pre-extraction are promising strategies to reduce the dissimilarities with bagasse, thus facilitating the development of feedstock-agnostic biorefining. [ABSTRACT FROM AUTHOR]

Water hyacinth (Eichhornia crassipes) as a aquatic weed has become a source of concern for value addition. This study aimed to determine the feasibility of the weedy biomass in sustainable bioethanol production using Phanerochaete chrysosporium and Saccharomyces cerevisiae. The results indicated that P. chrysosporium significantly utilized 70.9% of cellulose and 70% of hemicellulose from raw lignocellulose of water hyacinth with significant microbial enzyme production of 1.26 IU/ml. Moreover, the microbial treatment resulted in a significant amount of soluble protein (194.30 mg/g) and reducing sugar (34.20 g/l). XRD, SEM and FTIR analyses revealed that the crystalinity of cellulose was increased with the microbial treatment and hence, the yield of sugar also. Under submerged fermentation, Saccharomyces cerevisiae produced a maximum of 20.17 g/l of ethanol. The promising results of the present study explored the microbial treatment with P. chrysosporium and fermentation with S. cerevisiae as a successful and sustainable method for ethanol production from lignocellulosic weedy biomass. [ABSTRACT FROM AUTHOR]

Converting food waste, such as garlic straw, into bioethanol offers a promising solution for both food waste management and meeting the increasing energy demands of a growing population. As a low-cost and renewable agro-industrial substrate, garlic straw holds significant potential for bioethanol production. To optimize the enzymatic conversion, pretreatment was performed to facilitate the enzymatic saccharification process by alkaline peroxide and sodium chlorite, resulting in a substrate consisting of 83.07% cellulose, 6.13% hemicelluloses, and 2.09% lignin. The bleached garlic straw (BGS) was hydrolyzed using a cellulolytic complex produced by the hypercellulosic mutant Penicillium occitanis Pol6, aiming to convert cellulose into glucose. The BGS was treated with various enzyme loading (10–50 FPU/g), at different BGS concentration (20–80 g/L) and tween 80 concentration (0–8 g/L) and at different reaction time (24–72 h). The hydrolysis yield from enzymatic saccharification of BGS were evaluated using a Box–Behnken Design. The optimum conditions for the hydrolysis yield were obtained based on surface and contour plots. The maximum predicted hydrolysis yield of 54.08% was obtained as follows: enzyme loading 40 FPU/g, BGS concentration 22 g/L, Tween 80 concentration 6 g/L and hydrolysis time 72 h. Fermentation of hydrolysates of bleached garlic straw (HBGS) carried out using Saccharomyces cerevisiae for 24 h showed that the sugar content decreased over time, while ethanol production increased. Besides, the highest bioethanol production (11.9 g/L) was observed in the 4% HBGS sample after 6 h of alcoholic fermentation. These findings proved the economical production of ethanol using garlic straw as a cheap waste material and also using a low-cost enzymes derivated from filamentous fungi. [ABSTRACT FROM AUTHOR]

Researchers are developing new techniques for clean fuel production due to environmental problems such as global warming. In this respect, bioethanol is considered among the most important renewable fuels. This study aims to investigate the energy cycle and estimate the potential environmental effects of ethanol production from sugarcane bagasse in Iran. To this end, ethanol's life cycle assessment (LCA) was conducted based on the "cradle to gate" approach. This assessment includes three stages of sugarcane farming, transportation to the factory, and bioethanol production. This study defines three scenarios for bioethanol production from sugarcane bagasse using the fermentation conversion process: fermentation, bagasse burning for electricity, and combined bioethanol and electricity production. The third scenario was chosen as the best. However, in environmental analysis, it showed the most negative effects on environmental indicators, especially in cases of abiotic depletion and global warming potential. Scenario 1 showed better results than the others. The results showed that electricity, diesel fuel, and nitrogen fertilizer had the greatest environmental impact in the mentioned process. Moreover, by replacing fossil fuels with clean energies, more energy efficiency and less environmental consequences can be achieved because fossil fuels cause air pollution leading to acid rain, eutrophication, damage to forests, and harm to wildlife. Our results show that the bioethanol production process using sugarcane bagasse as feedstock requires 27.13 MJ/L input energy, while the total output energy is 40.44 MJ/L. Energy indices were calculated, with values of 1.49, 0.037, 27.13, and 13.31 for energy ratio, efficiency, intensity, and net energy addition, respectively. [ABSTRACT FROM AUTHOR]

Extortionate demand of global bioethanol has led to a burgeoning interest in finding the alternative sources of biofuel. For this purpose, researchers are interested in microalgae because of its biorefinery applications and ability to produce biofuels, and other value-added products. Bioethanol is the most extensively used renewable fuel and is one of the realistic candidates for addressing environmental issues and mitigating the low base of oil supply. Chlorella sorokiniana can be considered as the most eminent source of bioethanol due to the accumulation of high levels of carbohydrates which can significantly be converted into renewable, cost-effective, and eco-friendly bioethanol. Keeping in view the importance of pretreatment for the efficient production of biofuels, the present study was targeted to determine the optimum conditions required for the chemical pretreatment. The selected microalgae strain was cultivated under mixotrophic and photoautotrophic conditions at laboratory and pilot scales. For mixotrophic cultivation, 0.2% (v/w) of molasses was used as an organic source of carbon. The reducing sugar content of Chlorella sp. was studied by pretreating the dried biomass with dilute H2SO4 and NaOH at 3%, 5%, 7%, and 9% (v/v) concentrations. Mixotrophic cultivation conditions along with 3% H2SO4 pretreatment showed the most efficient recovery of entrapped sugars from algal cell wall consequently producing maximum amount of bioethanol. At lab scale, the biomass cultivated under photoautotrophic and mixotrophic conditions and pretreated with 3% acid produced maximum of 10.96 and 16.07 g/L ethanol, respectively, while maximum ethanol production of biomass cultivated under mixotrophic conditions in alkaline pretreatment was 12.21 g/L at 9% NaOH and in biomass cultivated under photoautotrophic conditions maximum 9.89 g/L of ethanol production was estimated at 5% NaOH. During pilot-scale cultivation, the mixotrophically cultivated biomass pretreated with acidic medium produced 13.45 ± 4.31 g/L ethanol and photoautotrophically cultivated biomass resulted into 10.8 ± 6.31 g/L of ethanol with 88 and 83% of substrate reduction, respectively. This study proofs that biomass of C. sorokiniana pretreated with H2SO4 can act as a possible alternative for the sustainable production of bioethanol. Optimum growth of C. sorokiniana by using molasses in mixotrophic culture conditions also addresses the ability of microalgae to treat wastewaters and use waste materials as a carbon source. For the commercial production of bioethanol from microalgae, results of the present study will be helpful. [ABSTRACT FROM AUTHOR]

Among the biggest issues facing the world now are fuel shortages and water contamination. Therefore, the goal of the current study was directed to produce bioethanol from Jatropha curcas leaves and use the residual wastes in the form of composite sheets for crystal violet (CV) removal. The leaves were collected from Jatropha curcas, irrigated by various irrigation sources; sewage-water (A), sewage-water-sludge (B), and tap water (C). The acid hydrolysis (4% H2SO4) of these leaves demonstrated that the hydrolysis of the Jatropha curcas leaves (A) produced higher values of total reducing sugars (≈ 21 g/l) than other leaves (B &C). Moreover, the bioethanol concentrations obtained from the fermentation of this hydrolysate (A) at the bioreactor scale using Candida tropicalis and Saccharomyces cerevisiae (≈10 and 7 ml/l, respectively) were relatively increased compared to the flask level (≈7 and 5 ml/l, respectively). Afterwards, the unhydrolyzed wastes were dried, grinded, and embedded in polyvinyl chloride (PVC) polymer forming sheets. The sheets were characterized using FT-IR, SEM, swelling, and porosity. The highest CV removal percent of 95.39%, after optimization, was achieved at 100 ppm crystal violet concentration using 2.5 g/l from PVC-A composite sheet after 180-min contact time. [ABSTRACT FROM AUTHOR]

The increase in rice straw production and their non-utilization is a major global challenge. Even though it is an eco-friendly feedstock for the bioconversion of energy production separation of cellulose from the rice straw fiber is one of the main limitations that obstruct the application of such lignocellulosic feedstock. In the present research work, acid-alkali pretreatment technologies were applied to the rice straw to increase enzymatic accessibility and improve cellulose digestibility. The rice straw was physically and chemically treated and the chemical pretreatment with 4% sodium hydroxide released a maximum cellulose of 120.33 mg/L. The constituents of cellulose, hemicellulose, and lignin were estimated while the functional groups were identified by using Infrared spectroscopy. Further, the morphological and structural characterization between the untreated and the treated rice straw were analyzed by Scanning Electron Micrograph (SEM) analysis which demonstrated a highly distorted structure in the pretreated biomass. Rice straw was used for the production of bioethanol, with simultaneous saccharification fermentation (SSF) yielding higher ethanol (21.77%) than separate hydrolysis fermentation (SHF) (11.65%) by using commercial enzymes and yeast isolates, and optimal production conditions were determined. Pre-treating rice straw with 4% NaOH, optimized enzyme concentration (2:1:1), and SSF with Saccharomyces cerevisiae or 72-hour incubation at pH 4 yielded the highest bioethanol production. mutagenesis using UV rays and chemicals like Ethidium Bromide (EtBr) and Ethyl Methane Sulfonate (EMS) improved bioethanol yield, with EMS treatment exhibiting the most significant increase i.e. with the wild strain (21.77%) and with the mutant strain (24.29%) was achieved. Such a strategy will be eco-friendly and effective for the reduction of biomass and the production of bioethanol at a much lower cost. [ABSTRACT FROM AUTHOR]

In this study, the fermentation process of bioethanol production conditions were optimized by response surface methodology. Mulberry molasses production waste was used as the only carbon source for yeast fermentation to produce bioethanol. Hydrodistillation (HD) and ohmic-assisted hydrodistillation (OAHD) methods were employed to concentrate the bioethanol. Fermentation time (48–168 h), waste matter rate (5–45%) and pH (5–7) were selected as independent variables. Alcohol concentration was treated as the response. Optimum fermentation conditions were determined as 96.894 h fermentation time, 45% waste ratio and pH 7. At these optimum conditions, alcohol concentration was determined as 3.77 ± 0.33%. While the distillate obtained in the HD method contained 22.50 ± 1.89% alcohol, it showed 27.72 ± 0.24% in the OAHD method. The energy consumption values for OAHD and HD was 2.92 ± 0.51 and 53.24 ± 1.74 Wh/mL bioethanol, respectively. Results of study showed that the OAHD could be a cost-effective and green method to distillation of bioethanol from mulberry molasses waste. [ABSTRACT FROM AUTHOR]

Second-generation bioethanol has garnered considerable interest among researchers due to its utilization of lignocellulosic biomass, such as rice straw, which is both cost-effective and readily available. Nonetheless, the economic viability of large-scale production of second-generation bioethanol remains a significant challenge. There is an urgent need for cost efficiency across three critical stages: pretreatment, hydrolysis, and fermentation. This paper reviews recent advancements in bioethanol production from rice straw and proposes a novel approach to enhance economic feasibility. The inherent recalcitrance of rice straw necessitates the implementation of an appropriate pretreatment method, as this step is crucial for the success of the hydrolysis process. While chemical pretreatment is frequently employed, it often results in increased waste generation and maintenance costs, thereby elevating the overall production expenses. Optimizing reactor configurations for enzyme production, hydrolysis, and fermentation can lead to substantial reductions in production costs. Although enzymatic hydrolysis utilizing commercial enzymes is the predominant method, on-site enzyme production has demonstrated significant cost advantages. Consolidated bioprocessing (CBP) integrates enzyme production, hydrolysis, and fermentation within a single reactor using a single strain or microbial consortium. However, the productivity of bioethanol production from rice straw via CBP is currently low. The proposed novel CBP aims to address the limitations of the original CBP by integrating pretreatment, enzyme production, hydrolysis, and fermentation in a single reactor with a microbial consortium. This innovative approach is expected to minimize contamination risks and reduce equipment installation costs, thereby improving cost-effectiveness. Nevertheless, the implementation of the novel CBP presents challenges, including the establishment of a stable and efficient microbial consortium and the determination of optimal process parameters. Addressing these challenges is essential for the successful application of the novel CBP at an industrial scale. [ABSTRACT FROM AUTHOR]

Biomass and organic residues are increasingly recognized as valuable resources for bioenergy production. Lignocellulosic biomass offers sustainable alternatives to fossil fuels for generation of bioenergy (such as biogas, bioethanol, biodiesel, and biohydrogen). Pretreatment plays a crucial role in a biomass biorefinery. It increases biomass homogeneity and production yields, thereby overcoming transportation and storage problems. However, the absence of a clear plan for biomass pretreatment represents a challenge for biomass conversion procedures. The socio-economic effects of biomass utilization are not unequivocally constructive. High investment and capital costs, technological maturity of biofuels, large-scale biomass supply, and policy and regulatory issues are among the key challenges. Despite these challenges, with the right strategies and solutions, complete biomass valorization is achievable. Solutions such as quick capital cost estimation, upgrading existing plants, optimizing biomass feedstock blends, utilizing waste biomass resources, and improving machinery efficiencies can address these challenges. Policy and regulatory challenges can be tackled through clear and long-term targets, financial and fiscal incentives, mandates and obligations, and sustainability governance supported by regulations and certifications. However, the realization of these benefits would depend on various factors such as the specific context of the biomass utilization, the available resources, and the market conditions. Thus, this work critically reviews the status of bioenergy production, the socio-economic challenges of biomass pretreatment, and its diversity in the bioenergy set-up. [ABSTRACT FROM AUTHOR]

Pretreatment is an important step in lignocellulosic bioethanol production which aims to reduce lignin content and break down lignocellulosic structure thereby increasing the accessibility of enzymes in hydrolysis. Therefore, this research explored the pretreatment process on oil palm empty fruit bunch (EFB) with CO2 impregnation followed by alkali explosion. EFB was impregnated with CO2 at 5 °C for 12 h. After impregnation, EFB was mixed with 2.5 M of NaOH solution (1:5 of S/L ratio) in an alkali explosion reactor. Alkali explosion was conducted at 150 °C, 4 kg/cm2 of pressure with the variation of reaction time for 15, 30, and 45 min. The parameters analyzed in this study include EFB recovery, EFB composition and characteristics, glucose yields, and ethanol yields. EFB composition was analyzed as cellulose, hemicellulose, and lignin while the characteristics of the EFB were examined in functional groups. The results indicated that combined pretreatment using CO2 impregnation followed by 15 min of alkali explosion obtained higher delignification of EFB, glucose, and ethanol yield than only alkali explosion for 30 min. The highest glucose and ethanol yields were 99.33 and 83.80 w/w% of glucose mass in EFB, respectively. These results prove that CO2 can be used as an impregnation agent in lignocellulosic pretreatment and could be combined with alkali explosion. [ABSTRACT FROM AUTHOR]

Thermophilic actinomycetes are commonly found in extreme environments and can thrive and adapt to extreme conditions. These organisms exhibit substantial variation and garnered significant interest due to their remarkable enzymatic activities. This study evaluated the potential of Streptomyces griseorubens NBR14 and Nocardiopsis synnemataformans NBRM9 strains to produce thermo-stable amylase via submerged fermentation using wheat and bean straw. The Box-Behnken design was utilized to determine the optimum parameters for amylase biosynthesis. Subsequently, amylase underwent partial purification and characterization. Furthermore, the obtained hydrolysate was applied for ethanol fermentation using Saccharomyces cerevisiae. The optimal parameters for obtaining the highest amylase activity by NBR14 (7.72 U/mL) and NBRM9 (26.54 U/mL) strains were found to be 40 and 30 °C, pH values of 7, incubation time of 7 days, and substrate concentration (3 and 2 g/100 mL), respectively. The NBR14 and NBRM9 amylase were partially purified, resulting in specific activities of 251.15 and 144.84 U/mg, as well as purification factors of 3.91 and 2.69-fold, respectively. After partial purification, the amylase extracted from NBR14 and NBRM9 showed the highest activity level at pH values of 9 and 7 and temperatures of 50 and 60 °C, respectively. The findings also indicated that the maximum velocity (Vmax) for NBR14 and NBRM9 amylase were 57.80 and 59.88 U/mL, respectively, with Km constants of 1.39 and 1.479 mM. After 48 h, bioethanol was produced at concentrations of 5.95 mg/mL and 9.29 mg/mL from hydrolyzed wheat and bean straw, respectively, through fermentation with S. cerevisiae. Thermophilic actinomycetes and their α-amylase yield demonstrated promising potential for sustainable bio-ethanol production from agro-byproducts. [ABSTRACT FROM AUTHOR]

In order to improve the process feasibility and cost function of bioethanol production, higher titres of biomass saccharifying cellulases need to be produced on commercial scale. Diverse lignocellulosic substrates including abundantly accessible paddy straw can be utilized as carbonaceous substrates for the production of cellulose hydrolysing enzymes. This study aims to meliorate milled and sequential acid/alkali pre-treated paddy straw as inducer-substrates for the synthesis of fungal secretomes from Penicillium mallochii repertoires under solid state and liquid shake flask fermentation (SSF and LSF, respectively). The analysis of enzymatic activities of the respective secretomes reinforced the cellulolytic potential of P. mallochii where the maximum cellulase production (Filter paper cellulase: 76.43, Carboxymethyl cellulase: 130.29, Avicelase: 18.6 and β-glucosidase: 83.59 U L−1) was exhibited under LSF conditions using pre-treated paddy straw as the inducer. The disorganisation of the cellulosic structure via hydrogen bond disruption, as indicated by FTIR analysis, after acid/alkali pretreatment allowed a better establishment of fungus on the substrate, thereby facilitating higher cellulase production. A maximum ethanol content of 11.63 g L−1 was obtained at 48 h of simultaneous saccharification and fermentation using pre-hydrolysed paddy straw at 10% (w/v) solid loading and a cellulase dosage of 25 FPU gds−1. These results affirm the utilization of paddy straw for cellulase and ethanol production in an integrated bioprocess that can further be explored and optimized for scale-up studies to cater industrial applications. [ABSTRACT FROM AUTHOR]

Last year on, September 9, 2023, India launched the Global Biofuel Alliance (GBA) along with other 8 countries during the G20 Summit in New Delhi. The core purpose of the alliance is to promote the biofuels at global front mitigating the whooping carbon emissions in turn tackle the climate changes. India remarkably achieved 10 percent ethanol blending in June 2022 and is expecting to the availability of E20 blend to 2025. The country is already blending 20 percent ethanol which is available at more than 1600 retail outlets across the country. Now, after launching the GBA, India may take leap forward in pushing ethanol not only as biofuel but also as an ideal solvent in cosmetic, pharmaceutical and allied sectors. The judicious utilization of both first- and second-generation feedstocks (1G and 2G) into ethanol production can cater its growing demand. In the present scenario, mixed ethanol (1.5G ethanol) could be a suitable choice harnessing 1G and 2G feedstock without compromising the food and feed requirements. This manuscript critically appraises the Indian ethanol program, production statistics of ethanol, availability of 1G and 2G feedstock, technology profile and commercialization status of ethanol in India. Considering the potential of ethanol business and government support, many potential private companies are embarking on ethanol as a potential blending in gasoline. Indigenous production of ethanol and its blend in gasoline would empower the Indian economics while saving the foreign exchange reserves as country imports more than 70% gasoline requirements. [ABSTRACT FROM AUTHOR]

The need for more efficient ethanol production methods from sugarcane-based substrates has necessitated the study of (very) high-gravity fermentation strategies. High gravity (HG) and very high gravity (VHG) fermentation are fermentation processes that involve fermenting substrates with significantly higher concentrations of sugars or solids than traditional fermentation methods, typically leading to higher ethanol yields and process efficiencies. This review provides a comprehensive overview of recent advancements, challenges, and future prospects in HG and VHG fermentation for ethanol production from sugarcane-based substrates. It was observed that sugarcane juice, molasses, and bagasse have been used for the production of ethanol. It was also observed from various studies that the use of tailored yeast strains, coupled with optimized process conditions such as fermentation temperature, residence time, pH, substrate concentration, aeration, additional supplements, and the presence of inhibitors, has yielded remarkable improvements in the fermentation efficiency of sugarcane-based substrates and ethanol yields. Additionally, challenges in implementing HG and VHG fermentation of sugarcane-based substrates, as well as recommendations for further research and development, are presented. This study's significance cannot be overstated, as it has the potential to advance biofuel technology by optimizing ethanol yields from sugarcane, thereby promoting sustainable energy solutions. [ABSTRACT FROM AUTHOR]

In this study, ethanol was produced via thermal-acid hydrolysis, enzymatic saccharification, and fermentation from the red seaweed Eucheuma denticulatum as a biomass. Also, the removal and further recovery of 5-hydroxymethylfurfural (5-HMF) from hydrolysates were investigated. The thermal-acid hydrolysis produced 38.37 g/L monosaccharides and 6.55 g/L 5-HMF under the optimized condition of 13.7% (w/v) seaweed slurry and 479 mM H2SO4 at 121 °C for 54 min. More monosaccharide (6.43 g/L) was obtained from subsequent enzymatic saccharification using 8 U/mL of commercial enzyme C-Tec2 at 45 °C for 36 h. By detoxification, 88.0% of 5-HMF was removed from seaweed hydrolysates using a 1:1 ratio of polyethylenimine (PEI) to 5-HMF (g/g) at a pH of 11.0 for 15 min. Ethanol fermentation of E. denticulatum hydrolysate was performed using wild-type and galactose-adapted Saccharomyces cerevisiae. The ethanol concentration was maximized to 19.56 g/L (YEtOH = 0.43 g/g) by fermenting detoxified E. denticulatum hydrolysate with galactose-adapted S. cerevisiae Furthermore, for the valuation of 5-HMF (removed from hydrolysate) as a platform chemical, 85.6% of 5-HMF was recovered from the PEI-5-HMF solution by H2SO4 at pH 1.0. [ABSTRACT FROM AUTHOR]

Carbohydrates are more likely to be found in lipid-extracted microalgal biomass, which can be used to produce bioethanol with different pretreatment methods. The objective of this study was to prepare lipid-extracted biomass of Scenedesmus sp. grown in anaerobically digested brewery effluent for bioethanol production. Pretreatments such as autoclave, microwave, oven, and water bath heating with alkalis (NaOH and KOH), acids (HCL and H2SO4), and H2O as hydrolytic agents, as well as optimization of an effective pretreatment method for carbohydrate and reducing sugar extractions, were used. Bioethanol was produced from lipid-extracted microalgal hydrolysate under optimum conditions. The findings showed that the highest contents of carbohydrates (222.59 ± 3.16 mg/g) and reducing sugar (150.52 ± 5.57 mg/g) were obtained using microwave pretreatment with HCl, whereas the lowest contents of carbohydrates (34.48 ± 1.36 mg/g) and reducing sugar (30.85 ± 3.22 mg/g) were obtained in water bath heating with H2O. After optimizing the main parameters of microwave pretreatment, the highest carbohydrate and reducing sugar contents were increased by 24.72% and 27.92%, respectively, at the optimum conditions. The maximum bioethanol yield of 0.1 g/g lipid-extracted microalgal biomass with a fermentation efficiency of 94.84% was obtained at a fermentation time of 24 h. This study demonstrated that lipid-extracted biomass of microalgae obtained from wastewater has a high potential for bioethanol production and, consequently, the development of microalgae-based biorefineries. [ABSTRACT FROM AUTHOR]

In recent years, ethanol has emerged as a popular additive for biodiesel/diesel blends, to decrease the carbon footprint left by combustion products. Nanoparticles added with biodiesel/diesel have promoted greater ignition and combustion rate, lower ignition delay, and reduced exhaust emissions. This study evaluated the filter performance of prosopis juliflora biodiesel and bioethanol mixed with diesel with selected nano particles, namely graphene(G) and graphene oxide(GO) nanoparticles. Different nano additive proportions of 50, 100, 150, 200, 250, and 300 ppm were blended in diesel blends of BED20 (10% biodiesel + 10% ethanol + 80% diesel) and the filtration characteristics of these fuel blends were evaluated to determine the best nanoparticle mixture. Tamson filter blocking tendency (TFBT) apparatus was utilized to determine filter blocking tendency (FBT). The filtration performance was measured by following the ASTM standard (D2068-14) for initial pressure, fuel temperature and fuel flow rate. Results found that the FBT tends to rise with the addition of additive proportion. It was seen that FBT values of 200 ppm of grapheme (G) nanoparticles and 250 ppm graphene oxide (GO) were found to be 1.32 and 1.4 respectively which inline the acceptable range (1.41). [ABSTRACT FROM AUTHOR]

The goal of the current work was to optimize the growth parameters needed to manufacture agarase enzyme from a non-marine PI strain of Bacillus subtilis on an agar-based medium. Using Plackett–Burman design (PBD), nine process parameters were evaluated, and agar, peptone, and yeast-extract were identified as the most significant independent factors influencing agarase production with confidence levels more than 90%. To evaluate the optimal concentrations of the indicated process parameters on agarase production, the Box–Behnken design (BBD) was applied. After optimization, B. subtilis strain PI produced 119.8 U/ml of agarase, representing a 1.36-fold increase. In addition the agar hydrolysate fermented products contain the liberated oligosaccharide acts as strong antioxidant which has 62.4% scavenging activity. Also, the agarase yields increased (1141.12, 1350.253, 1684.854 and 1921.863 U/ml) after substitution the agar with algal biomass of Carolina officinalis at different concentrations (2, 5, 10 and 15%), respectively. After completing the saccharification process, the resulted hydrolysate was used to produce ethanol through fermentation with Pichia pastoris yeast strain as an economical method giving yields (6.68317, 7.09748, 7.75648 and 8.22332 mg/ml), that are higher than using yeast extract peptone dextrose (YPD) medium (4.461 mg/ml). [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant renewable material in nature, which is converted to simple sugar, glucose, by cellulase enzymes. Cellulase enzymes are one of the most important industrial enzymes that are widely used in the production of biofuels. This study aimed to use wheat straw as a carbon source for Saccharomyces cerevisiae yeast cells to produce bioethanol. Physical grinding and phosphoric acid plus hydrogen peroxide chemical pretreatment methods were carried out for the removal of lignin and hemicellulose from the structure of wheat straw and obtaining a cellulose-rich material. Thermophilic filamentous fungi were isolated from cow manure, and two isolates were selected based on the levels of endoglucanase, exoglucanase, and total cellulase activities and identified based on DNA sequences of internal transcribed spacer regions. Hydrolysates were obtained from enzymatic hydrolysis of pretreatment wheat straw by thermophilic cellulase enzymes. Fermentation of Saccharomyces cerevisiae yeast cells was performed in hydrolysates for bioethanol production. Aspergillus fumigatus isolate indicated 147.11, 515.9, and 453.78 U/mg wheat straw for exoglucanase, endoglucanase, and total cellulase activities, respectively. These activities were, respectively, measured as 380.35, 730.24, and 372.76 U/mg wheat straw for Rhizomucor pusillus isolate. Pretreatment procedures functioned efficiently and increased the cellulose part of wheat straw up to 88.91%. Hydrolysates of pretreated wheat straw (obtained from Aspergillus fumigatus and Rhizomucor pusillus cellulase activities) resulted in 21.88 and 24.02 g/L (4.05 and 5.31%) bioethanol by Saccharomyces cerevisiae yeast fermentation, respectively. It seems that utilizing thermophilic cellulase enzymes and wheat straw is a promising economic process for bioethanol production. [ABSTRACT FROM AUTHOR]

For the production of bioethanol, bamboo is quickly becoming recognized as a promising feedstock among other bio-based sources with enormous promise. The age of the culm when it is harvested is the most important factor that determines whether or not bamboo may be used as a renewable supply. In this study, the responsive enhancements of Beema bamboo were investigated based on the age of the stem. Beema bamboo is a superior hybrid clone of Bambusa balcooa. For this investigation, the bamboo was harvested at various stages of its development and then subjected to a two-step pretreatment process (step 1 acid treatment and step 2 alkali treatment). The amount of sugar that can be recovered and the amount of ethanol that can be produced from the treatment have both been estimated using enzymatic hydrolysis of the pretreated bamboo. According to the findings of the study, different age groups of bamboo exhibited significantly different chemical compositions (p-value < 0.05). The two-step pretreatment and enzymatic hydrolysis of bamboo resulted in a 95% recovery of fermentable sugar and a theoretical maximum ethanol output of 92.2%. Two-year-old bamboo had the highest ethanol output (321L/Ton) across all age categories. Therefore, 2 years of age was the optimal harvesting age for maximizing sugar recovery for bioethanol production. [ABSTRACT FROM AUTHOR]

To establish economically viable production of cyanobacterial bioethanol and commercially valuable bioproducts, mass cultivation is required; however, the exorbitant cost of nutrients is a significant impediment. Currently, potatoes are used extensively in food-processing industries worldwide. These industries produce large quantities of potato peel wastes (PPW), often discarded in the exposed environment, causing ecological problems. As a supplement in the growth medium for cultivation of the marine Synechococcus elongatus BDU 10144, PPW was explored as an inexpensive source of nutrients. Different concentrations of PPW were added to the novel seawater-based medium as a mixotrophic nutritional supplement after physical pretreatment, and biomass and carbohydrate yields were examined for test cyanobacterium. At alkaline pH, PPW supplementation was found to be a promising stimulant for growth and total carbohydrate accumulation, with a marked decline in the cultivation period, doubling carbohydrate synthesis, and significantly increasing bioethanol and co-products production. This study thus demonstrated that 10% PPW supplementation augmented the carbohydrate pool by ~ 2.2-fold and bioethanol yield by ~ 2.3-fold with bioethanol conversion by > 40%. Moreover, the test cyanobacterium was recognized as a prolific producer of high-valued exopolysaccharides (EPS) and mycosporine-like amino acids (MAAs), which were validated using analytical methods like ultraviolet-spectroscopy and high-performance liquid chromatography. Conclusively, PPW could be exploited as a cost-effective, natural, and green nutrient supplement for cyanobacterial mass cultivation, which could aid in devising a sequential strategy for the integrated production of MAAs, EPS, and bioethanol under the "waste-to-wealth" approach. [ABSTRACT FROM AUTHOR]

The surge in global biofuel demand is propelled by intensifying concerns over climate change and effective waste management. Government mandates on biofuel blending further boost this trend, underlining the significance of selecting renewable feedstocks, such as bioethanol and biodiesel, for biofuel production. The importance of selecting an efficient biomass pretreatment method cannot be overstated, given its status as the most energy-intensive and chemical-reliant step in the biofuel production chain. Thus, pretreatment becomes a crucial determinant in the feasibility and economic viability of biofuel technologies. Amid a wide array of pretreatment strategies, identifying a method that is both effective and sustainable is crucial for advancing biofuel commercialization. This review aims to rigorously evaluate both traditional and novel pretreatment techniques and their environmental footprints, leveraging life cycle assessment (LCA) studies from existing literature. By examining the sustainability of various pretreatment methods, this paper provides a holistic and clear view, serving as an essential resource for policymakers and industry stakeholders. It outlines the challenges faced in each phase of an LCA and proposes viable solutions. Additionally, the review furnishes valuable insights, recommendations, and directions for future research in achieving sustainable biofuel production. [ABSTRACT FROM AUTHOR]

Lignocellulosic cellulose serves as a key source for bioethanol production. The efficient conversion of cellulose relies on three major cellulase components. High cost of cellulases and the need for a single microbe that produces all cellulase components in the right proportion and quantities are a few challenges in bioethanol production from cellulose. This investigation is an attempt in developing an enzyme cocktail involving recombinant thermostable cellulases (rMtEgl, rMtCel6A and rMtBgl3c) of the thermophilic mold Myceliophthora thermophila and testing their applicability in the conversion of agro residues to ethanol for the first time. The most effective pretreatment method for paddy straw and sugarcane bagasse was optimized. Pretreatment of sugarcane bagasse with sodium chlorite and acetic acid resulted in a 5.5-fold increase in total reducing sugar liberation, while, in paddy straw, total reducing sugar release increased by 9-fold, when biomass was treated with NaOH and microwaves compared to untreated biomass. The inclusion of recombinant enzymes in the enzyme cocktail supported 80–90% saccharification of pretreated paddy straw and sugarcane bagasse, which is 2-fold higher than that achieved using commercial enzyme mix alone. The ethanol production levels of 55.8 and 37.0 g/L, with the fermentation efficiencies of 80 and 76%, were attained from the pre-treated paddy straw and sugarcane bagasse hydrolysates, respectively. An appropriate blend of each enzyme component and pretreatment method tailored for the specific biomass is crucial for efficient biofuel production. [ABSTRACT FROM AUTHOR]

India is the second-largest producer of paddy in the world, with an estimated annual production of 165 metric tons (MT) and about 10.8 MT of rice bran. Partially utilized agro-industrial residues, de-oiled rice bran (DORB) is an unexplored substrate for the production of industrial enzymes. The present study focused on producing and optimizing fungal cellulases and xylanase enzymes by Aspergillus niger VSRK09 under SSF conditions. The effect of physiological parameters was confirmed by one-factor-at-a-time (OFAT), followed by the RSM-based FCCCD method using statistical design. The enzyme-producing abilities of A. niger VSRK09 were improved using a hybrid statistical tool viz. artificial neural network incorporated with a multi-objective genetic algorithm (MOGA-ANN). This study revealed that the MOGA-based model resulted in an optimized enzyme activity, i.e., 24.8 FPU gds−1 and 520 IU gds−1 of cellulase and xylanase, respectively, at incubation time of 3.5 days, a substrate to moisture (SM) ratio of 1:1, and inoculum size of 3.0 × 106 spores mL−1. The validation performance of ANN indicates that the designed model is trained and tested with a minimum mean square error and inserted in MOGA, which produced the best-optimized results. Saccharification of DORB released 320.5 ± 8.75 (mg gds−1) of reducing sugar which was subsequently converted to bioethanol using Saccharomyces cerevisiae yielded 13.48 ± 1.21 g L−1 ethanol. [ABSTRACT FROM AUTHOR]

This study was conducted to analyze the potential of producing bioethanol from sunflower stalks with the optimized pretreatment models on total sugar production from sunflower stalk (SS) utilization to decompose the lignocellulosic biomass to sugar. The accumulation variables were examined in the pretreatment model, including pretreatment temperature (30, 35, and 40 °C), NaOH concentration (1, 1.5, and 2%), and duration (1, 2, and 3 days). Total sugar production was optimized using response surface methodology (RSM) on central composite design (CCD) models. In addition, the economic strategy was carried out. It was found that sunflower stalks have properties that can be used to produce bioethanol. One kilogram of dried sunflower stalks containing 8.398 g of ethanol at 8% purity can be distilled. Economic feasibility and sensitivity analysis of the project showed that the economic net present value is about 31,875 US $ cost and benefit ratio equal 1.11, and the internal rate of return is about 10%. This investment feasibility assessment is for the dried chopped agricultural waste processing plants, and its output will be used as a raw material for ethanol production, which is worthwhile and could return the capital within 8 years. However, this project needs support from the public and private sectors, and the state may have a policy of paying subsidies to bioethanol producers to increase interest in the use of dried chopped agricultural waste. This will allow for the development of the local economy and provide an alternative way to select raw materials for bioethanol production. [ABSTRACT FROM AUTHOR]

Colombia's continuous contamination of water resources and the low alternatives to produce biofuels have affected the fulfillment of the objectives of sustainable development, deteriorating the environment and affecting the economic productivity of this country. Due to this reality, projects on environmental and economic sustainability, phytoremediation, and the production of biofuels such as ethanol and hydrogen were combined. The objective of this article was to design and develop a sustainable system for wastewater treatment and the generation of biofuels based on the biomass of the aquatic plant Eichhornia crassipes. A system that simulates an artificial wetland with live E. crassipes plants was designed and developed, removing organic matter contaminants; subsequently, and continuing the sustainability project, bioreactors were designed, adapted, and started up to produce bioethanol and biohydrogen with the hydrolyzed biomass used in the phytoremediation process, generating around 12 g/L of bioethanol and around 81 ml H2/g. The proposed research strategy suggests combining two sustainable methods, bioremediation and biofuel production, to preserve the natural beauty of water systems and their surroundings. [ABSTRACT FROM AUTHOR]

Bioethanol from cornstarch is the largest renewable liquid biofuel currently in use. However, corn is the basis of the population's diet in many countries so other feedstock must be considered. This article proposes non-conventional starch from Ramon tree (Brosimum alicastrum), a specie native to the Mesoamerican region and widely distributed in the Yucatan Peninsula, Mexico. Ultrasound has appeared as a promising green technique used to make physical, chemical, and biological processes, including enzymatic reactions, more efficient. Ultrasonic pretreatments (UL) alone and combined with commercial enzymes and enzymatic extracts of native fungi (Trametes hirsuta Bm-2) with a power of 70 W at 42 kHz, for 30 min at 45 °C, 60 °C, and 70 °C, were used. The results indicate that the pretreatment conditions do not inhibit the enzymatic activity; on the contrary, they decrease the operational temperature, giving the best results at 45 °C. All the treatments presented significantly higher dextrose equivalent values than the control without sonication. In the fermentation process, 91% efficiency was reached using the native strain Candida tropicalis PL-1, which infers yields of 314 and 235 L/ton of Ramon seed flour (RF) for samples pretreated by UL combined with α-amylase and raw enzymatic extract respectively. Based on the above, the ultrasonic treatment combined with enzymes applied to RF is outlined as an option of non-conventional starch pretreatment for the bioethanol production to avoid the use of basic food in the quest of clean energy. [ABSTRACT FROM AUTHOR]

Jatropha curcas L. as a member of Euphorbiaceae family had many copious applications due to its richness content of oil, cellulose, hemicellulose, and lignin. Therefore, this work was directed to increase the value of the seedcakes of Jatropha curcas by their applications in bioethanol production and removal of methylene blue dye (MB) as well as hexavalent chromium Cr (VI) from contaminated wastewater. The seedcakes sources were collected from different irrigation treatments: tap water (1), sewage water (2), sewage water and sludge (3), sewage water and sludge sprayed with tap water, 100, 200, 300, and 400 ppm of chlorocholine chloride (cycocel or abbreviated as CCC), (4), (5), (6), (7), and (8), respectively. Results showed that sewage water only (2) and the combination between sewage water and sludge irrigation (3) produced the highest ethanol quantity (4.59 & 5.15 ml/l, respectively) after the fermentation of the hydrolysates by Candida tropicalis Y-26. In respect to CCC spraying, the maximum ethanol concentration (5.57 ml/l) was achieved from Jatropha curcas seedcake irrigated with CCC at a concentration of (300 ppm). In the other application, a preliminary screening experiment was demonstrated for the different forms of Jatropha curcas seedcake and results revealed that the Jatropha curcas seedcake irrigated with sewage water only (2) achieved the highest removal efficiencies of 78.8% and 41% for MB and Cr (VI), respectively. After that, the optimization process stated the optimum parameters; Jatropha curcas seedcake dose of 15 and 5 g/l, conc. 50 ppm, pH 7 and 5, and contact time 240 & 120 min were the optimum factors that achieved high (methylene blue (MB)) and hexavalent chromium [Cr (VI)] removal efficiencies, respectively. Langmuir isotherm and the pseudo-first-order model were stated as selected models that explain the adsorption mechanism of MB and Cr by Jatropha curcas seedcake. [ABSTRACT FROM AUTHOR]

Exploring sustainable energy and chemical sources based on biomass has increased global interest. This study was focused on produce second-generation bioethanol using a new pretreatment process. The effectiveness of sodium hydroxide (NaOH) pretreatment on oil palm empty fruit bunch (OPEFB) for lignin removal, reducing sugar, and bioethanol production at low temperature and pressure was investigated using batch and continuous processes. Response surface methodology (RSM) was used to optimize the NaOH concentration and solid to liquor ratio (SL) at a maximum temperature of 100 °C and atmospheric pressure. The mathematical formula derived from RSM was based on 11 runs of the batch treatment. In the batch treatment process, 2 M NaOH, the temperature of 80 °C, and SL ratio of 8 have resulted in lignin removal of 38.7%, reducing sugars of 8.3%, and bioethanol concentration of 4.1%. The validation of formula has been calculated from calculation and experiment values. Moreover, at the same retention time, continuous pretreatment showed a reducing sugar content of 5.9% and a bioethanol concentration by 2.5%. The results show that the continuous process can be employed in effective bioethanol production from OPEFB. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass as a cheap and abundant raw material offers great advantages in terms of biotechnological applications. The current study aimed to produce bioethanol from mulberry pomace by newly isolated xylose/glucose co-fermenter Hanseniaspora uvarum. For this purpose, the xylose consumption capacity of the yeast was first tested using the synthetic xylose-containing medium as a carbon source, and Hanseniaspora uvarum effectively fermented xylose into ethanol. Afterward, Hansenispora uvarum was used for the fermentation of the liquid hydrolysate obtained by dilute acid pretreatment of mulberry pomace. Furthermore, a subsequent enzymatic hydrolysis of the pretreated mulberry pomace was performed to investigate its effect. For this purpose, initial biomass concentration (50–500 g/L) for fermentation was optimized in two different mulberry pomace media containing nitrogen sources or mineral salts. Enzymatic hydrolysis of pretreated mulberry pomace was performed at 400 g/L initial biomass loading with or without soluble soy protein addition, and a significant increase in fermentable sugar concentrations was observed. The highest sugar concentration was observed as 159.6 g/L when 400 g/L biomass loading was used during dilute acid pretreatment, and subsequent enzymatic hydrolysis was performed using 15 FPU/g cellulose. Moreover, after dilute acid pretreatment and enzymatic hydrolysis, ethanol production of Hanseniaspora uvarum reached 61.3 g/L (0.153 g/gbiomass) which is a sufficient amount for efficient distillation according to literature. Results show that xylose/glucose co-fermenter Hanseniaspora uvarum and mulberry pomace can be considered for second-generation bioethanol production. [ABSTRACT FROM AUTHOR]

Purpose: Globally, the demand for fossil fuels is a major issue that needs attention through replacement using bio resources. This work aims to carry out a comparative study on the production of biofuels from the rinds of Aloe vera and the pods of Delonix regia. Aloe vera rinds have several characteristics, like cellulose, vitamins, enzymes, sugars, lignin, saponins, etc. It was used as the lignocellulosic feedstock for bioethanol production due to the availability of cellulose and hemicellulose content, which can be hydrolyzed into fermentable sugars. Methods: In this research, a physiochemical method employing ionic liquid-assisted nanocatalyst was performed. Pretreatment was carried out along with the application of ultrasound waves to extract the fermentable sugars. The ultrasonication time, concentration of ionic liquid, and nanocatalyst was optimized to extract the maximum amount of fermentable sugars. The ultrasound treatment was found to be efficient for 20 min. Musa acuminata peels was used to synthesize copper oxide nanoparticles (CuO NPs). The size and shape of the CuO NPs was studied by scanning electron microscopy (SEM) analysis. Pretreatment of the Aloe vera rinds and Delonix regia pod was performed using ionic liquid-assisted nanocatalysts separately and in combination with the ionic liquid (triethyl ammonium hydrogen sulfate) and CuO NPs. The combined pretreatment step using the ionic liquid and CuO NPs with ultrasound extraction revealed the highest concentrations of fermentable sugars of 0.3 mg/ml and 0.21 mg/ml for Aloe vera rinds and Delonix regia pods, respectively. High performance liquid chromatography (HPLC) analysis was carried out in the hydrolysates of the feedstock after pretreatment. The cellulose and hemicelluloses content was found to be 0.82% and 0.26% for Aloe vera rinds, 23.65% and 12.67% for Delonix regia pods. Di-nitro salicylic acid assay (DNSA) was performed to estimate the hydrolyzed sugars. Fermentation using Saccharomyces cerevisiae was carried out with the extracted sugars and its growth kinetics were studied. The ethanol produced was 1.01 mg/ml from Aloe vera rinds and 0.81 mg/ml from Delonix regia pods. Conclusion: Thus, the combined pretreatment step increases the efficiency of extraction and the yield of fermentable sugars for bioethanol production. [ABSTRACT FROM AUTHOR]

In recent years, the efficient utilization of agro-waste to produce value-added products has gained more ground due to its inexpensive nature, abundance and solution to environmental problems. These agro-wastes are renewable resources. This study sought to explore different enzymes Aspergillus niger and Saccharomyces cerevisiae, for producing ethanol from plantain and yam peels using hydrolysis and fermentation. Hydrolysis and fermentation were performed separately to optimize the performance of the respective enzymes and fermenting microorganisms. Parameters monitored were moisture loss, the degree of hydrolysis, the amount of reducing sugar and the volume and concentration of bioethanol. Fifty grams each of the plantain and yam peels was milled into powder and thoroughly dried. The flour was mixed with 500 ml of distilled water and hydrolyzed with Aspergillus niger. The hydrolysates were fermented with Aspergillus niger, Saccharomyces cerevisiae, and ethanol was extracted from the broth by distillation. The yam peels produced a higher concentration of ethanol, 31.86% w/v and plantain, 22.72% w/v after completion of the 7-day fermentation with A. niger and S. cerevisiae. Fermentation of yam and plantain with A. niger was successful, taking 7 days for biomass conversion with yields of 11.4% w/v and 9.41% w/v, respectively. There was a significant difference in p-values of 0.0089 and 0.0311 in the concentration of ethanol produced from yam and plantain peels, respectively, with the various microorganisms. [ABSTRACT FROM AUTHOR]

In the present investigation, formulate the new ecofriendly, low-cost commercial fertilizer for pilot-scale cultivation of a green microalgae, Tetradesmus obliquus RDS01, using bubble column photo bioreactor. Initially, we optimized the four different fertilizers, viz., urea—500 mg L−1, di-ammonium phosphate (DAP)—350 mg L−1, potassium—280 mg L−1, and sodium bicarbonate—165 mgL−1 using response surface methodology (RSM). The Tetradesmus obliquus RDS01 microalga was produced 350.25 mg g−1 of lipid, 240.35 mg g−1 of carbohydrate, 17.50 g L−1 of biomass, 98.52% of CO2 utilization efficiency, 325 U mL−1 of acetyl CoA carboxylase enzyme, 5.73 mL g−1 of biodiesel, and 4.25 mL g−1 of bioethanol obtained in pilot-scale cultivation in optimized commercial fertilizer medium. The Acetyl CoA carboxylase enzyme protein molecular weight was observed at 64KDa on 15% SDS-PAGE. The 3D structure homology modeling of Acetyl CoA carboxylase enzyme protein structure was predicted and protein encodes with 498 amino acid residues. The Acetyl CoA carboxylase specific genes (aCCD) were 1230 bp isolated. The Tetradesmus obliquus RDS01 microalga–produced biodiesel was subjected to gas chromatograph mass spectrometer (GCMS) analysis and identified the 50 biodiesel compounds. The major biodiesel compounds, viz., Cis-8-methylicosanoate methyl ester (28.36%). Eicosanoic acid, methyl ester (12.36%), hexadecanoic acid methyl ester (13.15%), 14-heptadecatrienoic acid methyl ester (3.25%), tridecanoic acid methyl ester (10.96%), tetradecanoate methyl ester (11.35%), pentadecanoic acid methyl ester (12.57%). The presences of functional groups were identified from the biodiesel such as amides, alcohols, carboxylic acids, alkenes, alkenyl, carbonyl, and ketones groups using FTIR. The bioethanol was confirmed in the peak range 3.52 min by HPLC. [ABSTRACT FROM AUTHOR]

Liquid biofuels like biodiesel and bioethanol are crucial in the transition to low-carbon and high-energy alternatives to fossil fuels. One significant by-product of biodiesel production is glycerol, which accounts for about 10% of the total conversion output. While waste glycerol poses challenges due to its impurities and contaminants, it also holds potential as a metabolic resource for essential cellular components in microorganisms. Crude glycerol production is reviewed, highlighting relevance in current biodiesel technologies and its biochemical composition. To efficiently utilize waste glycerol, co-valorization with low-cost substrates through biocircular platforms using various microorganisms or insects for second and third-generation oxy-biofuels has been explored. Among these, the black soldier fly larvae have demonstrated higher competitiveness for lipid contents (35–43%), making them a promising organism for recycling waste glycerol into biodiesel production, alongside microalgae and oleaginous yeast. The microbial biodiesel productivity from oleaginous yeast is notably higher (3546 kg ha−1 y−1) than soybean biodiesel (562 kg ha−1 y−1), while microalgal biodiesel productivity surpasses palm biodiesel by more than 25 times. Remarkably, black soldier fly larvae biodiesel productivity was reported to be ~ 1.7 times higher than microalgae and an impressive ~ 43 times higher than palm biodiesel. Despite their potential for biodiesel production, waste glycerol from biodiesel industry still represents a challenge because of high impurities, high viscosity, and limited direct applications in existing processes. To further enhance energy sustainability and address the challenge of waste glycerol, biocircular platforms are discussed for waste glycerol utilization with domestic wastewater sludge, lignocellulosic biomass, and protein-rich wastes. These platforms offer opportunities to create other sustainable agricultural products while minimizing their environmental footprint. [ABSTRACT FROM AUTHOR]

In this study, the electro-oxidation reaction of ethanol over Pd–Cu supported on Cu porphyrin (TPPCu) was investigated. The catalyst was synthesized using the microwave-assisted polyol method and physicochemically characterized by XRD, XPS, SEM, EDS, TEM, EDAX, UV–Vis, FTIR, and RBS. A Cu-enriched catalyst with Cu3Pd, Pd,Cu, and TPPCu phases was identified using XRD and XPS. However, according to the RBS results, the catalytic surface was enriched with Pd, indicating that the interaction between TPPCu and Pd–Cu allowed the presence of Pd on the surface, thus enhancing the catalytic response of the material. This synthesis prevented the deprotonation of porphyrin on the electrocatalyst, as confirmed by XPS analysis. Electrochemical studies based on cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the response of the catalyst to variations in the scan rate and increasing ethanol concentration. The electrochemical response of PdCu/TPPCu improved with an increasing number of cycles, indicating improved mass transport, thus improving its electrochemical response and tolerance to CO contamination. This catalyst exhibited a high electroactive surface area of 49.4 m2/g, which could be related to the presence of TPPCu as a support. The behavior of the catalyst on the anode of a fuel cell fed with ethanol, bioethanol, and bioethanol residues was evaluated. [ABSTRACT FROM AUTHOR]

The uniqueness and relevance of the current work involve the production of bioethanol from the lignocellulosic biomass of two popular sweet sorghum varieties, viz., CSV19 and CSV24, using a yeast hybrid strain SP2-18, generated through genome shuffling. Bioethanol production from sweet sorghum bagasse varieties -CSV19 and CSV24 were examined utilizing three different alkali pretreatment techniques (PT1, PT2, and PT3). To determine the influence of the pretreatment procedure, a combination of alkali and hydrogen peroxide, with or without steam, was evaluated on the biomass of two promising varieties CSV19 and CSV24. To deconstruct the biomass, pretreatment procedures such as PT1 (2% NaOH, steam, and H2O2), PT2 (2% NaOH and H2O2), and PT3 (2% NaOH and steam) were used. The results revealed that bagasse processed with PT1 produced more bioethanol than the other two pretreatments, PT2 and PT3. Furthermore, Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to investigate the structural changes in biomass following pretreatment. The FTIR and SEM characterizations demonstrated that the microstructural changes of the pretreated sweet sorghum bagasse significantly differed from those of the untreated biomass. Enzymatic hydrolysis studies were also carried out on the pretreated sweet sorghum biomass (PT1, PT2, and PT3). Enzymatic hydrolysis yielded total reducing sugar concentrations of 58.62 g/L and 52.89 g/L in CSV19 and CSV24 sweet sorghum varieties respectively. Finally, we demonstrated that the resulting hydrolysate was used as a substrate and fermented with hybrid yeast strain SP2-18 derived from the parental strain Saccharomyces cerevisiae to convert the reducing sugars into bioethanol, a promising intermediate to biofuels and bioproducts. Genome shuffled yeast hybrid SP2-18 produced higher bioethanol productivity of 0.91 gL−1 h−1 and 0.85 gL−1 h−1 for CSV19 and CSV24 varieties of sweet sorghum respectively, as compared to parental strain S. cerevisiae which had bioethanol productivity of 0.56 gL−1 h−1 and 0.47 gL−1 h−1 respectively for sweet sorghum varieties of CSV19 and CSV24. [ABSTRACT FROM AUTHOR]