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AbstractIn the current work, cellulase from Aspergillus niger was successfully immobilized on a novel epoxy-affixed chromium metal-organic framework/chitosan (Cr@-MIL-101/CS) support via covalent method using glutaraldehyde as a crosslinker. The bare and cellulase-bound support was characterized by using various microscopic and spectroscopic techniques. Immobilized cellulase exhibited a high immobilization yield of 0.7 ± 0.01 mg/cm2, retaining 87.5 ± 0.04% of its specific activity and displaying enhanced catalytic performance. The immobilized enzyme was maximally active at pH 5.0, temperature 65 °C and 0.9 × 10–2 mg/ml saturating substrate concentration and the half-lives of free and immobilized cellulases were approximately 9 and 19 days, respectively. The decrease in activation energy, enthalpy change, and Gibbs free energy change, coupled with an increase in entropy change upon immobilization, indicated that the enzyme’s efficiency, stability, and spontaneity in catalyzing the reaction were enhanced by immobilization. Additionally, the immobilized cellulase efficiently converted rice husk cellulose to glucose, with a quantification limit of 0.05%, linear measurement ranging from 0.1 to 0.9%, and 8.5% conversion efficiency. The present method exhibited a strong correlation (R2 = 0.998) with the DNS method, validating its reliability. Notably, the epoxy/Cr@-MIL-101/CS-bound cellulase demonstrated impressive thermal and pH stabilities, retaining 50% of its activity at 75 °C and over 96% at pH levels of 4.5 and 5.0 after 12 h. Furthermore, it showed excellent reusability, preserving 80% of its activity after 15 cycles and maintaining 50% of its activity even after 20 days of storage. These results suggest that epoxy/Cr@-MIL-101/CS/cellulase composites could be very effective for large-scale cellulose hydrolysis applications. [ABSTRACT FROM AUTHOR]

The conversion of bioethanol to ethylene in gas phase and atmospheric pressure was investigated over γ‐Al2O3 supported copper and nickel catalysts. These catalysts were prepared by co‐precipitation and pre‐treated with hydrogen at 450 °C. Six catalysts were studied at 450 °C under a nitrogen atmosphere. It was found that the monometallic Cu/γ‐Al2O3 catalyst exhibited the highest ethylene concentration, with a selectivity of around 90 %. The bioethanol conversion obtained was between 57 %‐86 %. Another catalyst that exhibited high concentration values was the NiCu1 : 7 bimetallic catalyst. The catalysts were characterised using XRD, SEM, EDS, TEM, TGA, FTIR, Raman, and N2‐physisoption techniques. Furthermore, the Cu/γ‐Al2O3 catalyst was studied under different reduction temperatures and gas flow conditions. It was found that the catalysts reduced at 350 °C and 35 ml/min N2 flow presented ethylene concentrations between (0.18–0.21) g/L. Moreover, the catalyst deactivation was identified to be first order and the equation of the Cu/γ‐Al2O3 catalyst deactivation model was determined. Carbonaceous deposits over the used sample were not detected by Raman and FTIR. It was determined that the Cu/γ‐Al2O3 catalyst deactivation could be mainly attributed to the blocking of the catalytic sites by strongly adsorbed compounds and hydroxylation of the catalyst surface. [ABSTRACT FROM AUTHOR]

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]

Exo‐β‐(1,3)‐glucanases are promising enzymes for use in the biofuel industry as they hydrolyse sugars such as laminarin, a major constituent of the algal cell wall. This study reports structural and biochemical characterizations of Aspergillus oryzae exo‐β‐(1,3)‐glucanase (AoBgl) belonging to the GH5 family. Purified AoBgl hydrolyses β‐(1,3)‐glycosidic linkages of the oligosaccharide laminaritriose and the polysaccharide laminarin effectively. We have determined three high‐resolution structures of AoBgl: (a) the apo form at 1.75 Å, (b) the complexed form with bound cellobiose at 1.73 Å and (c) the glucose‐bound form at 1.20 Å. The crystal structures, molecular dynamics simulation studies and site‐directed mutagenesis reveal the mode of substrate binding and interactions at the active site. The results also indicate that AoBgl effectively hydrolyses trisaccharides and higher oligosaccharides. The findings from our structural and biochemical studies would aid in rational engineering efforts to generate superior AoBgl variants and similar GH5 enzymes for their industrial use. [ABSTRACT FROM AUTHOR]

Biomass pretreatment is essential to facilitate lignin removal and enhance cellulose concentration for optimal bioethanol production. Therefore, this research aimed to determine the effects of conventional KOH (KP) and Combined KOH microwave-assisted (CKMP) pretreatment on the banana stem (BS) composition, analyzing the kinetics of lignin removal at various temperatures and KOH concentrations for 25 min. Kinetics variables were calculated by fitting experimental data and cellulose was hydrolyzed to produce reducing sugars. The results showed that the highest lignin removal for KP and CKMP were 37.11%, and 40.39%, respectively, with CKMP having the lowest activation energy of approximately 2.688 kJ mol−1. CMCase and FPase activity were 1988.3474 and 1605.4187 U mL−1, respectively, which were significantly higher than the values reported in previous research. The maximum concentration of reducing sugars achieved was 17.69 g L-1, with an enzyme concentration of 50% (v/w), pH 5, and a hydrolysis duration of 25 h. Michaelis constant varied from 0.0037 to 0.0079, and the maximal rate ranged from 1.28 × 10−6 to 2.76 × 10−6 Mol L−1 s−1 when computing the reaction rate using the Michaelis–Menten kinetics model. [Display omitted] • The results of this study provided insight into producing bioethanol from banana stems. • Combined KOH microwave-assisted pretreatment (CKMP) of banana stem was carried out. • Lignin content was effectively removed at 43.02%. • Enzymatic hydrolysis kinetics followed the Michaelis–Menten kinetics model. • K M value was 0.0037–0.0079 and v max was 1.28 × 10−6 to 2.76 × 10−6 Mol L−1 s−1. [ABSTRACT FROM AUTHOR]

This paper investigates bioethanol production from switchgrass, focusing on enhancement of efficiency through various pretreatment methods and comparing two bioethanol production processes: simultaneous saccharification and fermentation (SSF) and separate hydrolysis and fermentation (SHF). Physical, chemical, and biological pretreatment processes are applied to enhance the breakdown of switchgrass's lignocellulosic structure. Effects of pretreatments, enzymatic hydrolysis, and fermentation on ethanol yield are discussed in detail. The comparative analysis reveals that SSF yields higher ethanol outputs within shorter times by integrating hydrolysis and fermentation into a single process. In contrast, SHF offers more control by separating these stages. The comparative analysis highlights that SSF achieves higher ethanol yields more efficiently, although it might restrict SHF's operational flexibility. This study aims to provide a comprehensive overview of the current pretreatments, hydrolysis methods, and fermentation processes in bioethanol production from switchgrass, offering insights into their scalability, economic viability, and potential environmental benefits. The findings are expected to contribute to the ongoing discussions and developments in renewable bioenergy solutions, supporting advancing more sustainable and efficient bioethanol production techniques. [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]

Forestry residues (FR) and medicinal-aromatic plant waste (MAPW) are considered potential resources for energy recovery. In this context, we explore the bioethanol production potential of three microbial strains Aspergillus niger, Zymomonas mobilis, and Trichoderma longibrachiatum using this lignocellulosic hydrolysate as a substrate. The blend of FR and MAPW was pretreated by different methods like acid sulfuric (AS), steam explosion (SE), and enzymatic (E). The ethanol yield was measured by gas chromatography (GC). Zymomonas mobilis demonstrated the highest ethanol yield of 5.95% on untreated substrate. Conversely, Aspergillus niger exhibited peak performance with an ethanol yield of 10.78% following AS, SE and E combined pretreatment. Trichoderma longibrachiatum, yielded ethanol ranging from 1.27% to 2.47%. Furthermore, the use of immobilized d' Aspergillus niger strains revealed a small decrease in ethanol yield from 11.34% in the first cycle to only 5.02% in the sixth cycle. In conclusion, Aspergillus niger emerges as a promising candidate due to its dual functionality in pretreatment and ethanol fermentation, offering pathways for advancing sustainable biofuel technologies. [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]

Enzymatic hydrolysis contributes to obtaining fermentable sugars using pretreated lignocellulose materials for bioethanol generation. Unfortunately, the pretreatment of lignocellulose causes low substrate enzymatic hydrolysis, which is due to the structure changes of lignin to produce main phenolic by-products and non-productive cellulase adsorption. It is reported that modified lignin enhances the speed of enzymatic hydrolysis through single means to decrease the negative effects of fermentation inhibitors or non-productive cellulase adsorption. However, a suitable modified lignin should be selected to simultaneously reduce the fermentation inhibitors concentration and non-productive cellulase adsorption for saving resources and maximizing the enzymatic hydrolysis productivity. Meanwhile, the adsorption micro-mechanisms of modified lignin with fermentation inhibitors and cellulase remain elusive. In this review, different pretreatment effects toward lignin structure, and their impacts on subsequent enzymatic hydrolysis are analyzed. The main modification methods for lignin are presented. Density functional theory is used to screen suitable modification methods for the simultaneous reduction of fermentation inhibitors and non-productive cellulase adsorption. Lignin-fermentation inhibitors and lignin-cellulase interaction mechanisms are discussed using different advanced analysis techniques. This article addresses the gap in previous reviews concerning the application of modified lignin in the enhancement of bioethanol production. For the first time, based on existing studies, this work posits the hypothesis of applying theoretical simulations to screen efficient modified lignin-based adsorbents, in order to achieve a dual optimization of the detoxification and saccharification processes. We aim to improve the integrated lignocellulose transformation procedure for the effective generation of cleaner bioethanol. [Display omitted] • Effects of pretreatment in lignin structure and enzymatic hydrolysis are analyzed. • Lignin modification is the promising enhancement process to bioethanol production. • DFT calculation contributes to screening the suitable lignin modification methods. • Advanced methods to study inhibitors-lignin-cellulase interactions are reviewed. [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]

Fossil resources must be replaced by renewable resources in production systems to mitigate green-house gas emissions and combat climate change. Electrofermentation utilizes a bioelectrochemical system (BES) to valorize industrial and municipal waste. Current electro-fermentation research is mainly focused on microbial electrosynthesis using CO2 for producing commodity chemicals and replacing petroleum-based infrastructures. However, slow production rates and low titers of metabolites during CO2 -based microbial electrosynthesis impede its implementation to the real application in the near future. On the other hand, CO is a highly reactive gas and an abundant feedstock discharged from fossil fuel-based industry. Here, we investigated CO and CO2 electro-fermentation, using a CO-enriched culture. Fresh cow fecal waste was enriched under an atmosphere of 50% CO and 20% CO2 in N2 using serial cultivation. The CO-enriched culture was dominated by Clostridium autoethanogenum (≥89%) and showed electroactivity in a BES reactor with CO2 sparging. When 50% CO was included in the 20% CO2 gas with 10  mA applied current, acetate and ethanol were produced up to 12.9  ±  2.7  mM and 2.7  ±  1.1  mM, respectively. The coulombic efficiency was estimated to 148%  ±  8% without an electron mediator. At 25  mA, the culture showed faster initial growth and acetate production but no ethanol production, and only at 86%  ±  4% coulombic efficiency. The maximum optical density (OD) of 10  mA and 25  mA reactors were 0.29  ±  0.07 and 0.41  ±  0.03, respectively, whereas it was 0.77  ±  0.19 without electric current. These results show that CO electro-fermentation at low current can be an alternative way of valorizing industrial waste gas using a bioelectrochemical system. [ABSTRACT FROM AUTHOR]

A substantial amount of process waste is generated during the manufacture of soft‐wheat products (SWPs), such as biscuits/cookies, crackers, wafers, and cakes. A small portion of waste is reused in specific biscuits, whereas the rest is usually discarded. This study aimed to investigate the suitability of this waste for the co‐production of bioethanol and fatty acid methyl esters (FAMEs or biodiesel). Two groups of waste generated in the SWP industry were included in the study: (a) the waste of low‐moisture (<10%) biscuits, crackers, and wafer sheets with no fillings and/or coatings, and (b) the waste of high‐moisture (>10%) biscuits, crackers, wafers, and cakes with fillings and/or coatings. The study involved extracting each sample with hexane, and the recovered fat was converted to the FAME through alkali‐catalyzed transesterification. The remaining carbohydrate‐rich fraction was then converted to bioethanol through amylolytic hydrolysis and yeast fermentation. A great portion (92.42%–93.17%) of the fat was extracted from the wastes and converted to the FAME with adequate yields (13.81–14.55 g FAME/g waste, dm) and acceptable conversion efficiencies (85.19%–89.04%). However, bioethanol production from the defatted carbohydrate‐rich fractions proceeded rather slowly, yielding only 16.54–18.02 (g ethanol per g of waste, dm), corresponding to fermentation efficiencies ranging from 43.32% to 48.29%. Upon the co‐production of FAME and ethanol, a considerable amount (50.93%–53.08%) of waste solids remained in the residue fraction. These findings indicated that production of the FAME with adequate yields and conversion efficiencies is viable from the SWP industry wastes; however, bioethanol yields and fermentation efficiencies are rather limited, which warrants further investigation. Practical Application: The soft‐wheat processing industry generates 1%–5% of total production as waste. The waste was studied to produce FAME and bioethanol. The fat was extracted from the waste and converted to FAME. Bioethanol yields and fermentation efficiencies are limited due to dough modifiers and antimicrobial additives used in SWP production. Further research is required to improve ethanol yield. [ABSTRACT FROM AUTHOR]

In this research, the energy potential of switchgrass (SG) was analyzed to find promising directions for producing bioenergy from this biomass. The first direction is determining the thermal energy of bioethanol extracted from SG biomass after its pretreatment, enzymatic hydrolysis (saccharification), and fermentation of the resulting glucose. It was established that after a two-stage pretreatment of 1 ton of SG with dilute solutions of nitric acid and alkali, the largest amount of bioethanol can be extracted with an energy potential of 4.9 GJ. It is also shown that by the utilization of solid and liquid waste, the production cost of bioethanol can be reduced. On the other hand, the direct combustion of 1 ton of the initial SG biomass used as a solid biofuel provides an increased amount of thermal energy of 18.3 GJ, which is 3.7 times higher than the energy potential of the resulting bioethanol extracted from 1 ton of this biomass. Thus, if the ultimate goal is to obtain the maximum energy amount, then another direction for obtaining bioenergy from biomass should be implemented, namely, direct combustion, preferably after pelletizing. Studies have shown that fuel characteristics of SG pellets such as the gross thermal energy and density of thermal energy are lower than those of wood pellets, but they can be improved if the SG biomass is densified into pellets together with binders made from polymer waste. [ABSTRACT FROM AUTHOR]

Elephant grass (EG), or Pennisetum purpureum, is gaining attention as a robust renewable biomass source for energy production amidst growing global energy demands and the push for alternatives to fossil fuels. This review paper explores the status of EG as a sustainable bioenergy resource, integrating various studies to present a comprehensive analysis of its potential in renewable energy markets. Methods employed include assessing the efficiency and yield of biomass conversion methods such as pretreatment for bioethanol production, biomethane yields, direct combustion, and pyrolysis. The analysis also encompasses a technoeconomic evaluation of the economic viability and scalability of using EG for energy production, along with an examination of its environmental impacts, focusing on its water and carbon footprint. Results demonstrate that EG has considerable potential for sustainable energy practices due to its high biomass production and ecological benefits such as carbon sequestration. Despite challenges in cost competitiveness with traditional energy sources, specific applications like small-scale combined heat and power (CHP) systems and charcoal production show economic promise. Conclusively, EG presents a viable option for biomass energy, potentially playing a pivotal role in the biomass sector as the energy landscape shifts towards more sustainable solutions; although, technological and economic barriers need further addressing. [ABSTRACT FROM AUTHOR]

One of the key guidelines in the European waste management policy is the diversion of waste from landfills, preventing harmful effects on human health and the environment and ensuring that economically valuable waste materials are efficiently recycled and reused through proper management. The organic fraction of municipal waste is abundant and contains biodegradable ingredients such lignocellulose, starch, lipids, pectin, and proteins, making it suitable for biotechnological production. Taking into account that a large amount of organic waste is disposed of in landfills, within this work, the amount of organic waste disposed of in the landfill in Banja Luka was considered. Four simulation model scenarios of the integrated production of bioethanol and biogas are generated, and their process and economic aspects are discussed. In the first two modelled scenarios, the pretreatment conditions (1% sulfuric acid and a different neutralization agent) were varied, while in the other two, the share of the amount of raw material used for the production of bioethanol, i.e., biogas, was varied (split factor: 10–90%). The modelled plant, with a designed capacity of 6 tons/h of organic waste, is a significant bioethanol producer, generating 5,000,000 L/year. The profitability indicators, when examined, revealed that dedicating a portion of the organic municipal waste input exclusively to biogas production leads to decreased process efficiency. Based on the modeled process parameters, ethanol's minimum feasible selling price is $0.6616 per liter, while regarding the composition of organic municipal waste, carbohydrates have the most significant impact on the viability of the process. The developed model represents an excellent basis for further development of this integrated bioprocess in such a way that it can be modified with new process parameters or economic or ecological indicators and used at all levels of bioprocess design. Additionally, the obtained sustainable integrated bioethanol and biogas production plant models could support forthcoming steps in municipal waste management by providing reliable data on the conditions under which the integrated process of bioethanol and biogas production would take place, as well as the technical feasibility and economic profitability of such organic municipal waste utilization. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass, the most abundant natural resource on earth, can be used for cellulosic ethanol production but requires a pretreatment to improve enzyme access to the polymeric sugars while obtaining value from the other components. γ‐Valerolactone (GVL) is a promising candidate for biomass pretreatment since it is renewable and bio‐based. In the present work, the effect of a pretreatment based on GVL on the enzymatic saccharification of white birch was evaluated at a laboratory scale and the importance of the washing procedure for the subsequent saccharification was demonstrated. Both the saccharification yield and the production of cellulosic ethanol were higher using a noncommercial enzyme crude from Talaromyces amestolkiae than with the commercial cocktail Cellic CTec2 from Novozymes. Furthermore, the production of extracellular cellulases by T. amestolkiae has been optimized in 2 L bioreactors, with improvements ranging from 40% to 75%. Finally, it was corroborated by isoelectric focus that optimization of cellulase secretion by T. amestolkiae did not affect the pattern production of the main β‐glucosidases and endoglucanases secreted by this fungus. [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]

This study investigates the relationship between corn prices in Brazil and the international market, considering a rise in corn ethanol production in Brazil's Midwest region since 2017. Did the entry of the corn ethanol industry in Brazil affect the relationship between domestic and international corn prices? A cointegration analysis was made with a monthly time series from May 2005 to August 2023 controlling for different exogenous events or shocks that may have affected global agricultural markets. The study's findings indicate a stable long‐term relationship between the international and Brazilian corn prices, with changes in international prices being predictors of variations in Brazilian domestic prices, while the opposite was not statistically supported. The study also found no evidence to support the claim that the entry of the corn ethanol industry into Mato Grosso state in 2017 impacted the prices paid to local producers. Therefore, the increase in Brazilian corn prices cannot be attributed to additional demand for corn by local mills, an important result that contributes to discussions such as food versus fuel and indirect land use change. [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]

Several nations are committed to developing an alternative energy source to achieve the net zero emissions (NZE) target. A typical alternative is bioethanol, which has been reported to be a renewable energy supporting the achievement of the target. Although banana pseudostem waste is often minimally utilized and discarded by the community, several studies have shown its potential to yield bioethanol due to the high cellulose content. Therefore, this study aimed to synthesize bioethanol from banana pseudostem waste (Musa balbisiana) pretreated with potassium hydroxide (KOH) microwave using hydrolysis and fermentation. The effect of yeast concentrations (8%, 10%, and 12%) and fermentation times (6, 7, 8, 12, and 13 days) on the pretreated sample was also analyzed. Fermentation was carried out using enzymatic kinetic modeling with Michaelis Menten's equations to determine the reaction rate. The results showed that the sample with 12% yeast and fermentation time of 13 days produced the highest ethanol content (41.5%). In addition, the appropriate kinetic modeling results were similar to Hanes Woolf's linearization modeling. The 10% yeast concentration led to KM values of 1.606×10-3 g mL-1 and Vmax of 6.837×10-4 g mL-1 h. [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]

Mandarin peel (MP) has gained attention as a feedstock for flavonoid recovery via the extraction process based on the biorefinery concept, but residues remain after the extraction. Toward an integrated biorefinery concept, this study aimed to valorize extracted MP (eMP) by using it in bioethanol production. For efficient fermentable sugar production, the effect of enzymatic hydrolysis conditions on sugar conversion from eMP was investigated, and the results showed that combining cellulase and cellobiase resulted in a higher enzymatic glucose conversion (78.2%) than the use of the individual enzymes (37.5% and 45.6%). Pectinase played an essential role in enhancing enzymatic arabinose conversion, and the optimal conditions were determined to be pH 4 and 90 units of the three enzymes. Under optimal conditions, the sugar yield was 199 g glucose and 47 g arabinose/kg eMP, and the hydrolysate was used in bioethanol fermentation. The results showed that the bioethanol production was 3.78 g/L (73.9% yield), similar to the control medium (3.79 g/L; 74.2% yield), although the cell growth of the yeast was slightly delayed in the eMP hydrolysate medium. This study highlights the potential of eMP as a low-cost feedstock for sugar and bioethanol production. [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]

The risks and challenges of the NEOM project on water bodies can be somehow resolved by using Cystoseria sp., a brown-green macroalga, and natural renewable resource species, which are appealing due to their sustainability, cost-effectiveness, and eco-friendliness. Lipid was extracted from Cystoseria sp. collected from Sharma beach, Neom, Tabuk, Kingdom of Saudi Arabia. It was treated with different solvents, petroleum ether, methanol, and petroleum ether:methanol (1:1), to obtain biofuel. Petroleum ether and methanol were the most significant solvents for extractions of six different hydrocarbon compounds, followed by methanol. Tetrahydradecane 5-methyl 60.03% in petroleum ether, 59.51% in methanol, and 51.39% in petroleum ether:methanol is obtained. Removal of 10 mg·L−1 methylene blue (MB) by alga using 0.2 g·L−1 of Cystoseria sp. and its residues after methanol extract was achieved in 120 min. Zeta potential analysis of alga confirms that different negative charges on adsorbent surfaces undergo conformational change with different solvents and adsorb the positively charged MB via electrostatic interaction force. The production of bioethanol efficiency percentage from Cystoseria sp. ranges from 5% to 68.97%. Hence, Cystoseria sp. can be a renewable resource to yield biodiesel and bioethanol and eliminate MB from wastewater, maintaining environmental sustenance and economic development.

Crop rotation has been a commercial practice for managing the sugarbeet cyst nematode (Heterodera schachtii, SBCN) since the 1950s. Research conducted in southern California established that SBCN populations decline at the rate of 49% to 80% per year, leading to estimates that three- to four-year rotations to nonhost crops would be sufficient to reduce SBCN densities to nondamaging levels. Following grower reports that much longer rotations were needed in central California, trials were conducted to establish the rate of decline of SBCN in the San Joaquin Valley. Ten commercial fields with a history of SBCN infestation were sampled periodically for up to 6.3 years. In each field, 10 circular subplots located 30.5 meters apart (each with a 6-m radius) were established with reference to a permanent landmark. On each sampling date, 12 subsamples from each subplot were taken randomly from the top 0 cm to 30 cm of soil and composited into a single sample. Standard techniques were utilized to extract and count cysts and eggs from soil samples. Average yearly rates of population decline in the sampled fields ranged from 11.4% to 25.8%. This finding has implications for SBCN management in California sugarbeets grown for biofuel, as the lower decline rates indicate that longer nonhost rotation periods than previously anticipated may be necessary.

Aim: Triticale is a well adaptable crop, tolerant of disease and abiotic stresses, and able to grow with good yields even in poor soil, thus representing a good choice to develop a new industrial agri-chain in Italy in a sustainability contest, to cope with its soil problems due to incoming desertification. Methods: Two triticale elite lines were grown in marginal lands in controlled field experiments. The lines were harvested at two different development stages, namely green mass and seeds, and suitable standard protocols were applied to test their potential to produce bioethanol in line with the emerging bioenergy processes. Results: The protocols applied were able to obtain bioethanol with a good yield from both feedstocks. In particular, very efficient fermentation kinetics was observed using seed feedstock, with a sharp curve between 15 h and 24 h, reaching 84% of the total alcohol obtained (final time 72 h). Conclusions: Therefore, the results of this research point to new sustainable potential for industrial applications of triticale crops in Italy. Furthermore, the high activity of the endogenous amylolytic enzymes, mainly α-amylase, and the high starch content suggest the potential use of triticale in other industrial applications, like the brewing industry.

Forestry residues (FR) and medicinal-aromatic plant waste (MAPW) are considered potential resources for energy recovery. In this context, we explore the bioethanol production potential of three microbial strains Aspergillus niger, Zymomonas mobilis, and Trichoderma longibrachiatum using this lignocellulosic hydrolysate as a substrate. The blend of FR and MAPW was pretreated by different methods like acid sulfuric (AS), steam explosion (SE), and enzymatic (E). The ethanol yield was measured by gas chromatography (GC). Zymomonas mobilis demonstrated the highest ethanol yield of 5.95% on untreated substrate. Conversely, Aspergillus niger exhibited peak performance with an ethanol yield of 10.78% following AS, SE and E combined pretreatment. Trichoderma longibrachiatum, yielded ethanol ranging from 1.27% to 2.47%. Furthermore, the use of immobilized d’ Aspergillus niger strains revealed a small decrease in ethanol yield from 11.34% in the first cycle to only 5.02% in the sixth cycle. In conclusion, Aspergillus niger emerges as a promising candidate due to its dual functionality in pretreatment and ethanol fermentation, offering pathways for advancing sustainable biofuel technologies.

Abstract 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.

Several nations are committed to developing an alternative energy source to achieve the Net Zero Emissions (NZE) target. A typical alternative is bioethanol, which has been reported to be a renewable energy supporting the achievement of the target. Although banana pseudostems waste is often minimally utilized and discarded by the community, several studies have shown its potential to yield bioethanol due to the high cellulose content. Therefore, this study aimed to synthesize bioethanol from banana pseudostems waste (Musa Balbisiana) pretreated with KOH microwave using hydrolysis and fermentation. The effect of yeast concentrations (8%, 10%, and 12%) and fermentation times (6, 7, 8, 12, and 13 days) on the pretreated sample was also analyzed. Fermentation was carried out using enzymatic kinetic modeling with Michaelis Menten's equations to determine the reaction rate. The results showed that the sample with 12% yeast and fermentation time of 13 days produced the highest ethanol content (41.5%). In addition, the appropriate kinetic modeling results were similar to Hanes Woolf's linearization modeling. The 10% yeast concentration led to KM values of 1.606 x 10-3 g mL-1 and Vmax of 6.837 x 10-4 g mL-1 h.

The abundantly available waste banana pseudostem fibers have attracted the paper and textile industries, however the stem-sap extracted during fiber processing remains underutilized. Although this sap comprising cellulosic sugars holds potential as a feedstock, its commercial viability in the renewable energy sector remains a challenge. Our study delves into this untapped resource by mechanically extracting sap from banana pseudostems and enhancing its reducing sugar content to approximately 35.5 g/L through acid hydrolysis and detoxification without concentrating the sap. Using separate batch fermentations with pentose and hexose fermenting strains such as Pichia stipitis NCIM 3499 and Saccharomyces cerevisiae ATCC 2601, we achieved bioethanol production efficiencies of 67.5 % and 70.03 %, respectively. Yield and cost analyses confirmed the feasibility of this approach for industrial application in low-economy settings. Furthermore, gene-interaction network and functional enrichment analysis identified 63 key genes involved in carbohydrate metabolism and ethanol conversion pathways within the fermenting organisms. Among these, the PGK1 gene and its direct interactors emerged as promising targets for future biotechnological enhancements aimed at boosting bioethanol production. This study not only underscores the renewable energy potential of unconcentrated banana pseudostem sap but also paves the way for innovative genetic interventions to optimize bioethanol yields.

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]

The global practice of blending bioethanol with petroleum fuels serves the dual purpose of reducing fuel costs and mitigating vehicular emissions. However, variations from the stipulated amount of bioethanol in petroleum fuels can be detrimental to engine longevity and performance. Notably, portable analytical devices capable of swiftly and accurately assessing fuel samples without necessitating prior pretreatment have been developed by researchers. This review aims to elucidate the advances and prevailing trends in analytical tools such as electrochemical, spectroscopic, electrical, optical fiber-based, and physical parameter-based techniques for the determination of blended fuel composition. [ABSTRACT FROM AUTHOR]

This study aims to obtain bioethanol according to the Indonesian National Standard (SNI) 7390:2012, obtain Gasohol according to the RON (Research Octane Number) standard in Pertalite, and produce alternative fuels that are more environmentally friendly. The bioethanol production process includes hydrolysis, fermentation, distillation, and adsorption, with Saccharomyces cerevisiae to ferment sugar in pineapple skin into ethanol with a content of 59.62% from a 5-day fermentation process with 4% Saccharomyces cerevisiae, 0.5% urea, 0.5% NPK. Bioethanol is then mixed with Pertalite in the composition of E5 (5 ml of bioethanol mixed with 95 ml of Pertalite) to E25 (25 ml of bioethanol mixed with 75 ml of Pertalite), lowering the flash point of the mixture from 29.8°C (E5) to 28.0°C (E25), increasing the density from 0.7239 gr.(cm3)-1 (E5) to 0.7250 gr.(cm3)-1 (E25) and the viscosity from 0.41 cSt (E5) to 0.49 cSt (E25). Still, the octane number (RON) tends to be stable at 91.4-95.6. As a result, the bioethanol content is close to SNI 99.5%, the bioethanol-Pertalite mixture improves several parameters but lowers the flash point, and the E25 mixture meets the RON standard of 95.6 for Pertalite.