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Abstract\nHIGHLIGHTSThe biomethanization of lignocellulosic wastes remains an inefficient and complex process due to lignin structures that hinder the hydrolysis step, therefore, some treatments are required. This work describes the addition of an enriched microbial consortium in the biomethanization of rice straw. The experiment was carried out in lab batch reactors following two strategies: (i) pretreatment of rice straw for 48 h using the enriched microbial consortium (dilution 1:100), and (ii) addition of this enriched microbial consortium (dilution 1:100) directly to the anaerobic reactors (bioaugmentation). The kinetic behavior was described using three models. As a result, the microbial consortium molecular characterization showed 58 different bacterial species, predominantly the Lactobacillaceae family (45.7%), and the Clostridiaceae family (19.1%), which were responsible for the positive effect obtained by bioaugmentation with methane yield increases of 16% (290 LNCH4/kgVS) respect to the control. All kinetic models applied fitted the experimental data for cumulative methane production, although the modified Hill model showed the best fit. Bioaugmentation strategies demonstrate their effectiveness in lignocellulosic biodegradation, but the novelty of this research lies in the application of an enriched microbial consortium obtained by the authors through soil isolation techniques, which are very inexpensive and affordable for developing countries.An enriched microbial consortium developed by using the effective microorganism’s technology and soils isolated was characterized.Rice straw anaerobic digestion was bioaugmented by the addition of the enriched microbial consortium.Bacterial community dynamics during rice straw anaerobic digestion were influenced by pretreatment or bioaugmentation strategies.Bioaugmentation increases the celluloses biomass availability and the methane yield (16%).Specific methanogenic activity and kinetic were influenced by adding the enriched microbial consortium.An enriched microbial consortium developed by using the effective microorganism’s technology and soils isolated was characterized.Rice straw anaerobic digestion was bioaugmented by the addition of the enriched microbial consortium.Bacterial community dynamics during rice straw anaerobic digestion were influenced by pretreatment or bioaugmentation strategies.Bioaugmentation increases the celluloses biomass availability and the methane yield (16%).Specific methanogenic activity and kinetic were influenced by adding the enriched microbial consortium. [ABSTRACT FROM AUTHOR]

Lactic acid (LA) is a versatile, optically active compound with applications across the food, cosmetics, pharmaceutical, and chemical industries, largely driven by its role in producing biodegradable polylactic acid (PLA). Due to its abundance, lignocellulosic biomass is a promising and sustainable resource for LA production, although media derived from these matrices are often rich in xylose and contain growth inhibitors. This study investigates LA production using a xylose-rich medium derived from Cynara cardunculus L. altilis DC stalks treated through steam explosion and enzymatic hydrolysis. The lactic acid bacteria strains Lacticaseibacillus casei, Paucilactobacillus vaccinostercus, and Pediococcus pentosaceus were grown on natural media, achieving yields of 0.59, 0.57, and 0.58 g LA/g total carbon consumed, respectively. Remarkably, on xylose-rich media, all supplied sugar was consumed, with LA yields comparable to those on complex media. These findings highlight the adaptability of these strains in the presence of inhibitors and support the potential of lignocellulosic biomass as a low-cost and sustainable substrate for effective PLA production. [ABSTRACT FROM AUTHOR]

The production of multienzymes complex that could act in different raw materials is needed to improve the bioethanol production process. We isolated bacteria from vegetable residues, identified as Bacillus velezensis (UPF-B1 and UPF-B2), which were able to simultaneously produce amylolytic and cellulolytic enzymes. The enzyme complex was produced by submerged fermentation in a media containing whole-grain triticale flour and sugarcane bagasse at pH 5.5 without supplementation with micronutrient solutions, reducing the media's costs. The combined use of raw materials (triticale and sugarcane bagasse) led to higher enzymatic activities, which is important given the need for the availability of raw materials for the industrial operation of enzyme and bioethanol production plants. The enzymes produced by UPF-B1 showed their optimum at pH 5.0–5.5 and 40 ºC, and those produced by UPF-B2 at pH 5.0–5.5 and 30–50 ºC. The multienzyme complex produced by the strain UPF-B2 allows the hydrolysis in mild temperatures, near to those of fermentation processes, avoiding the need for thermophilic yeasts in the fermentation step, being a desirable option to be used in simultaneous saccharification and fermentation processes of bioethanol production. [Display omitted] • This is the first report to identify Bacillus velezensis in fruit residues. • Enzyme complexes were produced by bacteria isolated from horti-fruit residues. • Bacterial enzymes showed industrial potential to act at pH 5.0–5.5 and 30–50 ºC. • Sugarcane bagasse and triticale were substrates as a cost-reduction strategy. [ABSTRACT FROM AUTHOR]

The use of lignocellulosic residues as feedstocks for biofuels production represents an economic and ecofriendly option, since they are generated as byproducts or wastes from different industrial areas. Nevertheless, a pretreatment method aimed at eliminating the lignin content of these residues must be performed. This is required in order to increase cellulose bioavailability, which favors the production of reducing sugars through microbial or enzymatic attack. Some performed pretreatments can be classified as physical, chemical, and physicochemical methods. Although such methods are the most used pretreatments, they are expensive and generate or make use of harmful compounds. Biological methods, by the action of microorganisms or their enzymes for lignin content reduction, may be regarded as an alternative, being cheaper and more friendly to the environment than the aforementioned methods. However, until now, biological pretreatments have not shown the same yield as the previously mentioned methods in both sugar recovery and biofuel production. In that sense, the aim of this work is to review the efficiency of these methods, with the goal of clarifying their advantages and disadvantages for improvement of biofuel production. [ABSTRACT FROM AUTHOR]

The energy use of fruit tree pruning represents a current alternative to achieving an energy transition toward clean biomass resources, which can substitute for fossil fuels and mitigate polluting emissions. In Mexico, avocado is one of the most important fruit crops, with approximately 260,000 ha planted. The pruning of avocado trees generates large amounts of biomass that are not fully exploited, lacking studies that analyze in depth the energy potential of pruning. This study aims to determine the potential energy use of avocado pruning as densified solid biofuels. The physical, chemical and energetic properties of two pruning fractions defined as class B (branches) and class BAL (branches and leaves) were determined. From class B, pellets were made, and their physical and mechanical properties were determined. Subsequently, the evaluated parameters of the pellets obtained were compared to European quality regulations to determine their quality and identify their potential uses. The characterization of avocado pruning indicates that class B generally has better physicochemical characteristics than class BAL to be used as solid biofuel. It was found that class B has a high calorific value (19.61 MJ/kg) and low ash content (1.2%), while class BAL contains a high amount of ash (7.2%) and high levels of N (1.98%) and S (1.88%). The manufactured pellets met most of the quality requirements for immediate use in the residential, commercial and industrial sectors at the regional level. [ABSTRACT FROM AUTHOR]

The extensive utilization of conventional plastics has resulted in a concerning surge in waste. A potential solution lies in biodegradable polymers mostly derived from renewable sources. Cupriavidus necator DSM 545 is a microorganism capable, under stress conditions, of intracellularly accumulating Poly(3-hydroxybutyrate) (PHB), a bio-polyester. This study aimed to identify optimal conditions to maximize the intracellular accumulation of PHB and its global production using natural media obtained by processing lignocellulosic residues of cardoon, a low-cost feedstock. An intracellular PHB accumulation was observed in all of the tested media, indicating a metabolic stress induced by the lack of macronutrients. Increasing C/N ratios led to a significant decrease in cellular biomass and PHB production. Furthermore C. necator DSM 545 was incapable of consuming more than 25 g/L of supplied monosaccharides. Surprisingly, in the samples supplied with 60 % of the pentose-rich liquid fraction, complete consumption of xylose was observed. This result was also confirmed by subsequent tests using Medium 1 growth media containing xylose as the sole carbon source. Using a diluted medium with a C/N ratio of 5, a PHB production of 5.84 g/L and intracellular PHB accumulation of 77 % w/w were respectively achieved. Finally, comparative shelf-life tests conducted against conventional pre-packaging materials in PP suggested that PHB films performed similarly in preserve ready-to-eat products. [Display omitted] • C. necator DSM 545 productively grew on lignocellulosic-derived culture media. • C. necator DSM545 accumulated up to 77 % w/w of intracellular PHB • A PHB production of 5.84 g/L was achieved with a C/N ratio 5. • PHB film demonstrated food packing performance comparable to conventional PP. • C. necator consumed all the xylose supplied in the growth media. [ABSTRACT FROM AUTHOR]

The northern zone of Costa Rica has extensive forestry and agro-industrial development, which generates a large number of lignocellulosic residues that do not have an economic value but could represent a vast energy potential. Therefore, the objective of this study was to determine the optimal size and location of an electricity generation plant from the forest and agro-industrial biomass. The researchers worked with two forest species residues (Gmelina arborea and Tectona grandis) and two agro-industrial residues (Ananas comosus and Saccharum officinarum), representing the most extensive cultivations in the region. The material was characterized, then GIS layers of the species cultivation areas were analyzed and related to the roads and protected areas to define the twelve potential points where the power plant should be installed. Later, the optimal supply radius of the plant and the optimal site conditions were determined. The study determined that the tree species have an average caloric power of 19,059.50 kJ/kg, significantly higher than agro-industrial (16,684.9 kJ/kg). It was determined that 1,056,527.67 tons of dry biomass are generated per year; 6.5% arboreal and 79.97% from A. comosus. The minimum electricity generation capacity is 15 MW with an annual consumption of 102,300 tons, which are available between 15 and 100 km away from the sites. The southeast area was the best positioned because of the biomass source and optimal environmental conditions for establishing the power plant. [ABSTRACT FROM AUTHOR]

Increasing awareness due to climate change have been stimulating the development of renewable energies. Slow pyrolysis is considered a good method to produce high calorific value char, especially using lignin-rich sources. Along with calorific value, the ignition temperature is another important factor to classify biofuels as it is the minimum required temperature for self-sustaining combustion. Pyrolysis is responsible not only for improving the calorific value of biomass, but also for increasing its ignition, thus demanding more energy for char combustion. Therefore, the production of a char with energetic potential and improved combustibility is important. Here, chars produced at 300–700 °C and blended with biomass were evaluated according to their higher heating value (HHV) and ignition temperature by thermal analysis. The ash content of chars produced at higher temperatures limited their energetic potential. Depending on the ratio, blending char with biomass improved its combustibility without compromising its HHV. [ABSTRACT FROM AUTHOR]

Cellulose is a natural, unbranched, and fibrous homopolymer that is a major component in several agroindustrial residues. The aim of this study was to extract cellulose from oat hulls and then to modify it using a green route to obtain esterified cellulose through reaction with organic acids employing the reactive extrusion process, which is a process that presents some advantages, including low effluent generation, short reaction times, and it is scalable for large scale use. Citric (CA) and succinic (SA) acids were employed as esterifying agents in different concentrations (0, 5, 12.5, and 20%). Modified cellulose samples were characterized by their degree of substitution (DS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (DRX), scanning electron microscopy (SEM), wettability, oil and water absorption capacities, and thermal stability. DS of modified samples ranged from 2.28 to 3.00, and FTIR results showed that the esterification occurred in all samples for both acids by observation of important bands at 1720 and 1737 cm−1 for samples modified with CA and SA, respectively. All modified samples presented increased hydrophobicity. The modification did not have an influence on the morphological structure or crystallinity pattern of all samples. This study proved to be possible to modify cellulose using a simple and ecofriendly process based on reactive extrusion with organic acids. [ABSTRACT FROM AUTHOR]

The effect of adding different lignins on the physical and mechanical properties of particleboards made with stems of hydrangea and pine using the urea–formaldehyde (UF) resin was evaluated. Four types of lignin were characterized by Fourier-transform infrared spectroscopy and Klason lignin: Cane Bagasse lignin, Pine China lignin, Kraft Brazil lignin, and ammonium lignosulfonate (LSA). Particleboards were prepared with four types of lignin in a 1:1 (w/w) UF/lignin ratio and compared with those prepared with the UF resin without lignin (control sample). Water absorption, thickness swelling, rupture modulus, and modulus of elasticity were measured. The type of lignin used does not have a statistically significant difference in the physical and mechanical properties and also a decrease in the physical properties of the particleboards compared with the control sample. The use of LSA in the 3:1 (w/w) UF/lignin ratio allows to elaborate particleboards with mechanical properties like those found in the control sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two Trichoderma strains were isolated from the rhizospheric soil of medicinal plants. • Fermentation factors of lignocellulosic residues by Trichoderma strains was assessed. • Substrate components was a crucial factor affecting fermentation results. • T. afroharzianum showed pronounced cellulose degradation efficiency for corn straw. • Two Trichoderma strains would be useful for application in waste materials treatment. To achieve an economically viable substitutive strategy for lignocellulosic residues use, cellulose degradation by efficient Trichoderma strains become a key alternative. This study aimed to explore the effects of various cultural conditions on the degradation of different lignocellulosic substrates (corn straw and licorice residues) by Trichoderma longibrachiatum and Trichoderma afroharzianum in solid state fermentation. The strains were isolated from the rhizospheric soils of medicinal plants. In addition, the best fermentation combination was selected to evaluate the degradation results. This study confirmed that fermentation conditions and different components of corn straw and licorice residues were both crucial factors affecting the cellulase activity and spore production of two Trichoderma strains. A combination of T. afroharzianum degrading corn straw was selected for Response Surface Methodology optimization. The best fermentation conditions were fermentation time of 5.72 days, initial material liquid ratio of 1:4.58, initial pH of 6.32 and fermentation temperature of 28.8 ℃, with a filter paper cellulase activity of 0.91 U/mL. After continuous fermentation, the spore production reached 6.18 × 109 spores/g, the crude fiber degradation rate reached 23.5 % with the reducing sugar content maintained at 11 mg/g. These results highlight the great potential of T. afroharzianum degrading corn straw for organic amendment. [ABSTRACT FROM AUTHOR]

The xylonate was bioproduced directly from lignocellulosic residues, and the application properties of crude xylonate powder were investigated with a promising potential as a bio-based concrete water reducer. The overall integrated process was evaluated on the view of mass balance and techno-economic analysis using Aspen Plus modeling. 56 g/L of calcium xylonate (XA-Ca) can be obtained within 8 h from acidic corncob hydrolysate (ACH) at a 100 % yield with the whole-cell catalysis of Gluconobacter oxydans. At the addition of 0.2 wt% in the dry concrete content, XA-Ca powder and sodium xylonate powder prepared from pure xylose and ACH could reduce water used in concrete by 15 %, 14 %, 13 %, and 13 %, respectively. XA-Ca from ACH led to a 33% increase in concrete compressive strength and a 24% increase in concrete flexural strength at day 7 compared to the blank group. The techno-economic analysis showed the minimum XA-Ca powder price to be $ 0.806/kg which can be economically feasible. This study provides a practical and economical process prototype for the industrial concrete water reducer application of novel bio-based xylonate produced from lignocellulosic residues. [Display omitted] • Xylonate powder is produced directly from lignocellulosic residues. • Xylonate is tested for concrete water-reducer. • 0.2 wt% of XA-Ca reduces 15% water used for concrete. • Aspen plus models xylonate bioproduction and application. [ABSTRACT FROM AUTHOR]

This six-month study aimed to evaluate the removal of total nitrogen (TN) in two duplicated partially saturated (PS) vertical flow (VF) wetlands added with corncob in two different heights of the free-drainage zone (FDZ) after two years in operation. Both PS VF wetlands efficiently removed organic matter measured as biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) as well as total suspended solids (TSS) achieving average mass removal efficiencies of 95.3%, 83.2% and 92.9%, respectively, in system I (SI) and 96.3%, 84.0% and 94.9%, respectively, in system II (SII); with no significant differences (p > 0.05) between the systems. Measurements of oxidation-reduction potential (ORP), dissolved oxygen (DO), pH and electrical conductivity (EC) showed suitable conditions in the saturated zone (SZ) of the systems for denitrification process. TN removal was similar in both systems (p > 0.05) (51.5% and 52.9% in SI and SII), and decreased in 15% with respect to the first year. This decrease was due to the lower denitrification capacity of the FDZ as a result of the reduction in the supply of biodegradable carbon by corncob. Denitrification occurred in the SZ, but not at a sufficient level to increase TN removal. Novelty First, the use of lignocellulosic residues in partially saturated vertical wetlands to promote total nitrogen removal is very recent. Furthermore, to the best of our knowledge, this is the first study evaluating TN removal after two years of operation in this type of wetland. Therefore, this study allows us to better understand the function of these systems, in a relatively long term. Thanks to this study: it is possible to confirm that the main process of TN elimination is through the simultaneous nitrification-denitrification process in the free drainage zone (denitrification in the saturated zone is irrelevant) and that TN elimination decreases due to the reduction in carbon supply from the corn, in this area. [ABSTRACT FROM AUTHOR]

The laccase producing abilities of four Basidiomycete fungi species were compared using solid-state fermentation using four different lignocellulosic residues. The biosynthetic potential of the Basidiomycetes was highly dependent on the type of fungi. In general, the laccase secreting ability of Cerrena unicolor Han 849 was greater than Lenzites betulinus Han 851, Stropharia rugosoannulata Han 1321, and Auricularia heimuer Han 1333. The maximum laccase production of C. unicolor Han 849 was approximately 11.25, 122.26, and 15.27 times higher than L. betulinus Han 851, S. rugosoannulata Han 1321 and A. heimuer Han 1333, respectively. Different species of fungi had a preference in lignocellulosic residues. The presence of Firmiana platanifolia was conducive to secreting laccase via C. unicolor Han 849 during solid-state fermentation. A continuous and stable laccase production via C. unicolor Han 849 was an obvious advantage of solid-state fermentation with any of the four lignocellulosic residues used. The maximum laccase production of C. unicolor Han 849 using Firmiana platanifolia was approximately 2.12, 1.68, and 6.13 times higher than Populus beijingensis, Sorghum bicolor, and Oryza sativa, respectively. These findings will be helpful for developing new productivity strains in industrial applications and selecting suitable lignocellulosic residues for laccase production. [ABSTRACT FROM AUTHOR]

BACKGROUND: Orange bagasse (OB) is an agroindustrial residue of great economic importance that has been little explored for the extraction of cellulose. The present study aimed to investigate different combinations of chemical (sodium hydroxide, peracetic acid and alkaline peroxide) and physical (autoclaving and ultrasonication) treatments performed in one‐step processes for cellulose extraction from OB and to characterize the materials obtained according to their composition, morphology, crystallinity and thermal stability. RESULTS: The processing yields ranged from 140 to 820 g kg−1, with a recovery of 720–1000 g kg−1 of the original cellulose. Treatments promoted morphological changes in the fiber structure, resulting in materials with higher porosity, indicating partial removal of the noncellulosic fractions. The use of combined chemical treatments (NaOH and peracetic acid) with autoclaving was more efficient for obtaining samples with the highest cellulose contents. CONCLUSION: Therefore, ACSH (processed by autoclaving with NaOH) was the most effective one‐step treatment, resulting in 71.1% cellulose, 0% hemicellulose and 19.0% lignin, with a crystallinity index of 42%. The one‐step treatments were able to obtain materials with higher cellulose contents and yields, reducing reaction times and the quantity of chemical reagents employed in the overall processes compared to multistep conventional processes. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The present study aimed to optimize the enzymatic hydrolysis process to degrade cellulose from corn stubble (Zea mays), using enzymes from Aspergillus niger. During the first phase of the experimentation, the content of dry matter, organic matter, ash, crude protein, ethereal extract, lignin and cellulose content of the stubble was determined, using the reference methods of the U. Florida 1970 for its quantification. Subsequently the pre-drying and grinding of the same was carried out, prior to the alkali and acid-alkali pre-treatment processes applied, being dried at 4 different temperatures (45, 50, 55 and 60 ®C). The pretreated residues were subjected to hydrolysis with Aspergillus Niger cellulases (39,125 EU) at different pHs (4.0, 4.8 and 5.6), for 24, 48 and 72 h. at 45, 50, 55 and 60 ®C temperature; quantifying the concentrations of reducing sugars released during digestion. Finally, it was determined that the hydrolysis of the stubble without pretreatment and drying at 60 ®C, at a pH of 4.8 for 72 h., had high concentrations of reducing sugars, becoming an alternative for its use as food or biofuel, after the application of biotechnological processes. [ABSTRACT FROM AUTHOR]

Densification and torrefaction are potential technologies to valorize lignocellulosic residues into cleaner and sustainable alternative energy carriers for domestic, institutional, commercial and industrial thermal energy applications. Therefore, this review paper has focused on sources of lignocellulosic biomass for energy production. Furthermore, the processes involved in production of raw and torrefied briquettes/pellets have been discussed. Additionally, the physicomechanical, emissions and combustion properties of raw and torrefied briquettes produced from lignocellulosic residues have been presented. Also, the economics of briquetting lignocellulosic biomass materials have also been reviewed. The quality of densified solid biomass fuels from lignocellulosic residues was found to dependent on the feedstock and pretreatment conditions. Additionally, torrefaction and densification have been reported to upgrade the energy properties of loose biomass materials, as potential alternative fuel to firewood and charcoal. Finally, the economic profitability of densification projects has been found to be dependent on the availability of feedstocks, technology used and market potential of the product. [ABSTRACT FROM AUTHOR]

The use of different lignocellulosic residues for the production of cellulosic ethanol is an alternative for the expanding demand of this fuel without increasing the planting area of traditional carbohydrate crops. One of the proposed alternatives is the use of pineapple leaf fibers (PALF) residues, which is a material rich in cellulose that can be used as raw material for second-generation (2G) ethanol production. In this study, the PALF was pretreated using an alkaline medium combined with a steam explosion and the 2G ethanol produSction was analyzed by two-way processes to enzymatic hydrolysis using separated hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). Using SHF, the alcoholic fermentation process with addition of molasses provided good fermentability and can handle larger loads of carbohydrate in shorter fermentation time. The SSF was a better method for 2G ethanol production from PALF yielding 96.12%. Therefore, PALF is presented as good raw material for production of 2G ethanol, with all the environmental and social advantages of such approach. [ABSTRACT FROM AUTHOR]

Microbial lipid production using renewable raw material is considered an alternative for biodiesel production. In this study, several biotopes have been targeted for new oleaginous yeasts isolation. 205 yeast strains were screened to find efficient and more suitable oleaginous yeasts for agro-industrial wastes bioconversion. Using the qualitative fluorometric technique, 12 strains were pre-selected and the morphology of their lipid bodies was studied. The molecular identification showed that our isolates are closely related to six genera of oleaginous yeast. Cultivated on nitrogen limited medium, lipid content of all yeast strains exceeds 20% (w/w), confirming their oleaginous character. The highest lipid yield and content were achieved by Candida viswanathii Y-E4 (3.55 g/L) and Rhodotorula babjevae Y-SL7 (39.17%), respectively. All the lipid profiles analyzed are mainly formed by triacylglycerols of oleic acid. In addition to the lipogenic aptitude, the hydrolytic potential including cellualse and lipase activities was also studied. The highest CMCase (0.11 U/mL) and β-glucosidase (0.55 U/mL) activities were produced by the Trichosporon asahii Y-SL1 strain. However, the highest lipase activity (50 U/mL) was detected in the liquid culture of Yarrowia lipolytica Y-D1P. To minimize the SCO production cost, oleaginous yeasts were evaluated for their capacity to use agro-industrial by-products for lipids and enzymes production. Cultivated on wheat bran acid-hydrolysate, Rhodotorula mucilaginosa Y-MG1 exhibits the highest lipid yield (2.2 g/L). In parallel, a considerable lipid content 64% (w/w) and lipase activity (174.1 U/mL) were achieved by Yarrowia lipolytica Y-D1P and Trichosporon asahii Y-D1 respectively, when the soap stock of pomace olive oil refining was used as carbon source. This study opens up new perspectives in the use of industrial wastes for production of microbial lipids and high-added value products. [ABSTRACT FROM AUTHOR]

Barley hull hydrolysate was used as the fermentation feedstock of Trichosporon cutaneum CTM-30125 yeast strain for production of microbial lipid as the potential raw material of biodiesel. An effective hydrolysis process based on the combination of dilute acid hydrolysis and enzymatic saccharification was developed to maximize recovery of total sugars. On synthetic media, CTM-30125 can assimilate glucose and xylose simultaneously and accumulated intracellular lipid up to 43.6% (w/w). However, when grown on acid barley hull hydrolysate (ABHH) the lipid content was low (16.6% w/w) and a detoxification step was required. Overtiming by Ca(OH)2 treatment and adsorption by activated charcoal improved the fermentability of ABHH significantly by removing the inhibitors and reducing the nitrogen content. The solid fraction resulting from the acid treatment of the barley hull was treated with hydrolytic enzyme complex produced by the hyper-cellulolytic fungal strain Trichoderma reesei Rut C-30. Enzyme production and hydrolytic conditions were optimized to enhance the saccharification. The structural changes in native and treated raw material were monitored using FTIR spectra. Detoxified ABHH and enzymatic hydrolysate were successively fermented by the CTM-30125 strain in fed-batch bioreactor without addition of external nitrogen source. A total biomass of 17.5 g/L with a lipid content of 38.2% (corresponding to a lipid yield of 6.7 g/L) could be achieved after 168 h of culture. The relative fatty acid composition indicates the presence of increased levels of saturated (41.2%) and monounsaturated (52.5%) fatty acids in the oil, making it ideal for biodiesel production. [ABSTRACT FROM AUTHOR]

This paper presents a general review of the use of plastic and lignocellulosic waste in the production of Wood Plastic Composites (WPC). Wood-Plastic Composites are proposed as a solution to the growing generation of waste. Different mixtures of polymer matrices (plastics) and vegetable reinforcements (lignocellulosic residues) have been evaluated for the WPC production. The mixing of this type of raw material is mainly done using three types of technologies: extrusion, injection and compression molding. It was found that changes in the mechanical properties of the final product depend on the raw material type, the particle size and the fiber proportion used, as well as the addition of binding agents. In the same way, variations in the water absorption capacity, densification and thermal stability of the final compound are reported to increase the amount of fiber in the mixture. [ABSTRACT FROM AUTHOR]

Barley hull hydrolysate was used as the ferm entation feedstock of TV ichosporon cutaneum CTM-30125 yeast strain for production of microbiallipid as the potential rawmaterial of biodiesel. An effective hydrolysis process based on the combination of diluteacid hydrolysis and enzymaticsac charification was developed to maximize recovery of total sugars. On synthetic media, CTM-30125 can assimilate glucose and xylose simultaneously and accumulated intra cellularlipid up to 43.6% (w/w). However, when grown on acid barley hull hydrolysate (ABHH) the lipid content was low (16.6% w/w) and a detoxification step was required. Overtiming by Ca(OH)2 trea tment and adsorption by activated charcoal improved the fermentability of ABHH significantly by removing the inhibitors and reducing then itrogen content. The solidfraction resulting from the acid treatment of the barley hull was treated with hydrolytic enzyme complex produced by the hyper-cellulolytic fungal strain Trichoder mareesei Rut C-30. Enzyme production and hydrolytic conditions were optimized to enh ance the saccharification. The structural changes in native and treated rawmaterial were monitored using FTIR spectra. Detoxified ABHH and enzymatic hydrolysate were successively fermented by the CTM-30125 stra in in fed-batch bioreactor with out addition of external nitrogen source. A total biomass of 17.5 g/L with a lipid content of 38.2% (corresponding to alipid yield of 6.7 g/L) could be achieved after 168 h of culture. The relative fatty acid composition indicates the presence of increased levels of saturated (41.2%) and monounsaturated (52.5%) fatty acids in the oil, making it ideal for biodiesel production. [ABSTRACT FROM AUTHOR]

The properties and capacities of the ligninolytic enzymes of Daedaleopsis spp. are still unknown. This is the first study on the effect of plant residues and period of cultivation on the properties of Mn-oxidizing peroxidases and laccases of D. confragosa and D. tricolor, as well as their ligninolytic potentials. Wheat straw was the optimal carbon source for synthesis of highly active Mn-dependent peroxidases (4126.9 U/L in D. confragosa and 2037.9 U/L in D. tricolor). However, laccases were the predominant enzymes, and the best inducer of their activity (up 16000.0 U/L) was cherry sawdust. Wheat straw was the most susceptible plant residue to the effect of the enzymes, and extent of lignin degradation was 43.3% after 14 days of fermentation with D. tricolor. However, D. confragosa was a more effective lignin degrader, as it converted even 21.3% wheat straw lignin on the 6th day of cultivation. The results of the study clearly showed that delignification extent depends on mushroom species and on the type of plant residue, which is extremely important for potential use in biotechnological processes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Critical analysis of lignocellulose residue conversion was performed. • Key technologies for fuel production from were discussed. • Technical challenges in fuel cost reduction were presented. • Future directions on the lignocellulosic-fuel process were proposed. Lignocellulosic wastes have emerged as a potential feedstock in the last decades. There are multiple reasons for its abundance, easy availability, economic, and abundant sources. It can be used to produce several value-added products. Among them, fuel is considered one of the important requirements. Production of fuel from lignocellulosic biomass is a tricky business. The major reason for its failure is the low product yield. Therefore, high yield and low-cost are the two key parameters which need significant optimization. To achieve the target several newer technologies such as pyrolysis, hydrothermal liquefaction and gasification have emerged. These techniques are much more efficient than that of conventional acid or alkali. At the same time quality of the product is also improved. The focus of this review is to analyze the efficiency of chemical conversion of lignocellulosic residues into valuable fuels keeping in mind the cost-reduction strategies. [ABSTRACT FROM AUTHOR]

The use of agricultural residues for bioenergy production is gaining importance at a global scenario. There are multiple options to convert these residues into bioenergy carriers such as thermochemical processes (e.g., gasification). In this paper, a techno-economic assessment is carried-out to compare the stand-alone and biorefinery production of hydrogen through gasification as potential scenarios for bioenergy production. Experimental gasification procedures were carried out aiming to determine initial conditions and parameters for the simulation approach. The results demonstrated that the production of hydrogen based on the concept of a biorefinery can improve the profitability of the processes compared to that based on the stand-alone way. Thermochemical processes seem to be a potential technology for bioenergy production in Colombia; however, it also needs to be benchmarked with other technologies in order to provide insights on future development of bioenergy programs in Colombia. [ABSTRACT FROM AUTHOR]

Technological development has enabled the production of new value-added products from lignocellulosic residues such as lignin. This has allowed the forest industry to diversify its product portfolio and maximize the economic returns from feedstock, while simultaneously working towards sustainable alternatives to petroleum-based products. Although previous research has explored industrial-scale production opportunities, many challenges persist, including the cost of woody biomass and its supply chain reliability. While numerous studies have addressed these issues, their emphasis has traditionally been on bioenergy, with little focus on biochemical, biomaterials, and bioproducts. This review seeks to address this gap through a systematic study of the work recently reported by researchers. A lot of work has been published from United States and Canada with an emphasis on bioenergy production (84.8%), 4.6% of the work is focused on biomass to materials and chemicals, and 10.6% addressed both. Between 2012 and 2015, the majority of published research focused on biomass to materials and chemicals and both biomass to energy and biomass to materials and chemicals. This fact highlights recent interests in diversified biorefinery portfolios. However, further work concerning forest biomass supply chain optimization and new high-value bio-based materials and chemicals is necessary. [ABSTRACT FROM AUTHOR]

A detailed characterization of the main types of blue agave bagasse (BAB) obtained from the four largest tequila factories in the State of Jalisco (Mexico) is presented here. After milling/sieving the agave bagasses, two particle size fractions were identified, one rich in fibers and the other consisting of dust/fine particles. Both fractions were analyzed to determine the content of cellulose, hemicellulose, lignin, organic-soluble compounds, absorbed remaining sugars, minerals, and organic matter. After detailed analyses of both fractions by wet, thermal (thermo-gravimetric analysis (TGA)/differential thermo-gravimetric analysis (DTA)), and other methods (high-performance liquid chromatography (HPLC), microscopy, particle size by laser diffraction light scattering, and crystallinity by X-ray diffraction), a moderate-to-intensive method was devised for further processing the fibrous fraction, which had a high crystalline cellulose content, as well as for its subsequent enzymatic saccharification under well-defined moderate conditions. Alternative processing options were also devised for the dust/fine particle fraction, which has a moderate crystalline cellulose that is rich in adsorbed sugars and that has a high mineral matter content. [ABSTRACT FROM AUTHOR]

The impact on dark fermentation of seven carbohydrates as model substrates of lignocellulosic fractions (glucose, cellobiose, microcrystalline cellulose, arabinose, xylose, xylan and wheat straw) was investigated. Metabolic patterns and bacterial communities were characterized at the end of batch tests inoculated with manure digestate. It was found that hydrogen production was linked to the sugar type (pentose or hexose) and the degree of polymerisation. Hexoses produced less hydrogen, with a specific selection of lactate-producing bacterial community structures. Maximal hydrogen production was five times higher on pentose-based substrates, with specific bacterial community structures producing acetate and butyrate as main metabolites. Low hydrogen amounts accumulated from complex sugars (cellulose, xylan and wheat straw). A relatively high proportion of the reads was affiliated to Ruminococcaceae suggesting an efficient hydrolytic activity. Knowing that the bacterial community structure is very specific to a particular substrate offers new possibilities to design more efficient H 2 -producing biological systems. [ABSTRACT FROM AUTHOR]

Biomass from agricultural residues, especially lignocellulosic biomass, is not only seen as a sustainable biomass source for the production of electricity, but increasingly as a resource for the production of biogas and second generation biofuel in developing countries. Based on empirical research in an irrigated rice-growing area, Office du Niger, in Mali, this article builds scenarios for the sustainable potential of rice straw. The paper concludes that there is great uncertainty regarding the size of the sustainable resources of rice straw available for energy, but that the most likely scenario estimates a resource of about 120,000 t, which would permit up to three 5 MW el rice straw-fuelled power plants. Based on the findings from the empirical studies, the article further suggests that recently published research on the potential of rice straw in a number of African countries seems first to underestimate the uncertainty of resource assessments, and secondly to overestimate the resources available for energy production, mainly due to optimistic residue-to-product ratios and availability factors. [ABSTRACT FROM AUTHOR]

Agriculture and forestry yield enormous lignocellulosic biomass resources to produce bioenergy and bioproducts. To fully convert lignocellulosic biomass into high-value chemical components and manufactured products, phosphoric acid plus hydrogen peroxide (PHP) pretreatment was selected to fractionate them into cellulose-rich, water-soluble polysaccharides, and lignin fractions, and further upgraded into biofuel and biomaterials correspondingly. Results showed that the recalcitrant structure of the employed lignocellulose can be well disrupted the PHP, by which almost 100 % hemicellulose and 50.5–83.6 % lignin in these lignocellulosic biomasses can be removed. Correspondingly, the accessibility of cellulose hydrolytic enzymes was enhanced and achieved 100 % cellulose-glucose conversion, thus maximumly producing 18.4 g of bioethanol from 100 g of poplar hardwood. The acid hydrolysis ability of PHP facilitated the production of water-soluble polysaccharides with a high carbohydrate purity (98.3 %). The oxidation ability of PHP introduced additional carboxylic groups and aliphatic chains in lignin, which enhanced the amphiphilic properties of lignin to form uniform and stable lignin nanoparticles. The tailored PHP multiple product platform is thus applicable to achieve full conversion of agriculture and forestry residues into bioproducts as a sustainable biorefinery. [Display omitted] • Maximum converted lignocellulose waste into three high value-added bioproducts. • Multifunctional PHP technology allowed the facile upgradation of lignocellulose. • The maximum ethanol yield achieved at 18.4 g from 100 g lignocellulose by SSF. • The resulting high-value water soluble-polysaccharides exhibited high purity. • Mixed aromatic-aliphatic structure enhanced the amphiphilicity of lignin. [ABSTRACT FROM AUTHOR]

Bioethanol is the main biofuel used in Brazil and USA, produced from sugarcane and corn. Nevertheless, the use of food to produce ethanol has to be replaced by agroindustrial waste or energy crops. The alternative raw material for bioethanol production in Mexico could be sugarcane and blue agave bagasses. In this work, we built a complete simulation process using Superpro Designer ® software considering only the upstream units of fermentation for the technical and economical evaluation of lignocellulosic ethanol. Such consideration is based on a state-of-the-art analysis of the technology, indicating that technical and economical bottlenecks include pretreatment, saccharification and hexoses and pentoses fermentation. The simulation was carried out at different efficiency levels through a statistical analysis of surface responses and, three different saccharification processes to analyze ethanol production in terms of complete substitution of oxygenates in gasoline distributed in Mexico. The results indicate that ethanol production cost is 1.34 and 1.46 USD/gallon and potential production is 40.13 and 1380 MM gallon/year using blue agave bagasse and sugar cane bagasse, respectively. [ABSTRACT FROM AUTHOR]

This work investigates the mechanical and service behaviour of high-density polyethylene composites reinforced by sorghum stalk rind (SSR) at various concentrations of fibres and maleic anhydride treated polyethylene (MAPE). Fibre length l and aspect ratio l/w distributions of compounded fibre composites show large numbers of smaller particles. Tensile and bending properties were investigated, taking the effects of some service conditions into consideration, such as water absorption and UV exposure. Untreated polyethylene reinforced with 40 wt.% SSR showed a maximum water uptake of 6.9 wt.%. Generally, reductions in strength and modulus were observed upon immersion in water. In contrast, UV radiation did not show any significant effect on mechanical properties at exposure times of up to 300 h. [ABSTRACT FROM AUTHOR]

Biochemical composition and reactivity are key factors controlling the biodegradability of lignocellulosic residues. In the present study, 14 lignocellulosic substrates including 6 agricultural and 8 forest residues were analyzed for 9 biochemical characteristics, including BioMethane Potential (BMP), Biological Oxygen Demand (BOD), Enzymatic Cellulose Degradation tests (ECD), Van Soest and NREL fractionation methods. The data obtained were exploited by principal component analysis (PCA) and other statistical methods to investigate the possible correlations between the parameters. The study showed that the contents in particular lignin or in non-extractible residues (RES) were the characteristics which influenced most the anaerobic biodegradability (BMP), while the influence of the soluble fraction was quite low. BMP was well correlated with the ratio of the contents in non-lignin over lignin fractions and the cellulose to lignin ratio. Regarding agricultural residues, BMP was better correlated with lignin content than with RES content. Agricultural and forest residues exhibited distinct characteristics of aerobic and anaerobic biodegradability. Good correlation was observed between ECD and lignin content. Finally, it was also observed that Van Soest's and NREL methods did not provide the same results in terms of biochemical composition. [ABSTRACT FROM AUTHOR]

In solid-state anaerobic digestion, so-called ss-AD, biogas production is inhibited at high total solids contents. Such inhibition is likely caused by a slow diffusion of dissolved reaction intermediates that locally accumulate. In this study, we investigated the effect of H 2 and CO 2 partial pressure on ss-AD. Partial pressure of H 2 and/or CO 2 was artificially fixed, from 0 to 1 557 mbars for H 2 and from 0 to 427 mbars for CO 2 . High partial pressure of H 2 showed a significant effect on methanogenesis, while CO 2 had no impact. At high P H 2 , the overall substrate degradation decreased with no accumulation of metabolites from acidogenic bacteria, indicating that the hydrolytic activity was specifically impacted. Interestingly, such inhibition did not occur when CO 2 was added with H 2 . This result suggests that CO 2 gas transfer is probably a key factor in ss-AD from biomass. [ABSTRACT FROM AUTHOR]

In this study, the effect of total solid content (TS) on thermophilic hydrogen production from wheat straw was investigated. Six TS contents ranging from wet to dry conditions (10-34% TS) were tested in batch tests. A decrease of H2 yields was observed and three statistical groups were distinguished according to the TS content: wet conditions (10% and 14% TS) with 15.3 ± 1.6 NmlH2 gTS-1, intermediate conditions (19% TS) with 6.4 ± 1.0 NmlH2 gTS-1 and dry conditions (25-34% TS) with 3.4 ± 0.8 NmlH2 gTS-1. Such a decrease in biohydrogen yields was related to a metabolic shift with an accumulation of lactic acid under dry conditions. Concomitantly, a microbial population shift was observed with a dominance of species related to the class Clostridia under wet conditions, and a co-dominance of members of Bacilli, Clostridia classes and Bacteroidetes phylum under dry conditions. [ABSTRACT FROM AUTHOR]

Highlights: [•] The biochemical composition of different parts of wheat straw was characterized. [•] Morphological fractions showed strong composition differences. [•] Leaves had the higher methane potential contrary to stem structures. [•] A similar and low hydrogen production was obtained for every fraction. [•] Straw variety or harvesting methods optimization could increase methane production. [ABSTRACT FROM AUTHOR]

Background In solid-state anaerobic digestion (AD) bioprocesses, hydrolytic and acidogenic microbial metabolisms have not yet been clarified. Since these stages are particularly important for the establishment of the biological reaction, better knowledge could optimize the process performances by process parameters adjustment. Results This study demonstrated the effect of total solids (TS) content on microbial fermentation of wheat straw with six different TS contents ranging from wet to dry conditions (10 to 33% TS). Three groups of metabolic behaviors were distinguished based on wheat straw conversion rates with 2,200, 1,600, and 1,400 mmol.kgVS -1 of fermentative products under wet (10 and 14% TS), dry (19 to 28% TS), and highly dry (28 to 33% TS) conditions, respectively. Furthermore, both wet and dry fermentations showed acetic and butyric acid metabolisms, whereas a mainly butyric acid metabolism occurred in highly dry fermentation. Conclusion Substrate conversion was reduced with no changes of the metabolic pathways until a clear limit at 28% TS content, which corresponded to the threshold value of free water content of wheat straw. This study suggested that metabolic pathways present a limit of TS content for high-solid AD. [ABSTRACT FROM AUTHOR]

Abstract: The ethanol industry in North America uses starch derived from corn as its primary feedstock. In order to better understand the geographical distribution of advanced ethanol production, potential sources of lignocellulosic biomass for the process are considered. It is shown that the corn-producing regions of North America already support significant amounts of ethanol production, and that few unexploited sources of corn remain for the industry to utilize. Accessing other sources of sugar, including other types of biomass such as lignocellulosic materials, will become necessary for the industry as it expands, quite apart from the need to meet government mandates. The ability of bioconversion and thermochemical conversion to generate biofuels from lignocellulosic biomass is reviewed. The availability of lignocellulosic residues from agricultural and forestry operations is described, and the potential biofuel production associated with these residues is described. A residue-based process could greatly extend the potential of the ethanol industry to become a substantial contributor to the fuel and energy requirements of North America. It is estimated that ethanol production from residues could provide up to 13.7% of Canada’s 2009 transportation fuel demand, and up to 5.2% of the United States’ 2010 fuel demand. Utilizing lignocellulosic biomass will extend the geographic range of the biofuel industry, and increase the stability and security of this sector by reducing the impact of localized disruptions in supply. Development of a residue-based industry will help create the technologies needed to process energy crops as North America moves towards greater transportation fuel independence. [Copyright &y& Elsevier]

Abstract: Enzyme production is a growing field in biotechnology and increasing attention has been devoted to the solid-state fermentation (SSF) of lignocellulosic biomass for production of industrially relevant lignocellulose deconstruction enzymes, especially manganese-peroxidase (MnP), which plays a crucial role in lignin degradation. However, there is a scarcity of studies regarding extraction of the secreted metabolities that are commonly bound to the fermented solids, preventing their accurate detection and limiting recovery efficiency. In the present work, we assessed the effectiveness of extraction process variables (pH, stirring rate, temperature, and extraction time) on recovery efficiency of manganese-peroxidase (MnP) obtained by SSF of eucalyptus residues using Lentinula edodes using statistical design of experiments. The results from this study indicated that of the variables studied, pH was the most significant (p < 0.05%) parameter affecting MnP recovery yield, while temperature, extraction time, and stirring rate presented no statistically significant effects in the studied range. The optimum pH for extraction of MnP was at 4.0–5.0, which yielded 1500–1700 IU kg−1 of enzyme activity at extraction time 4–5 h, under static condition at room temperature. [Copyright &y& Elsevier]

Abstract: The excess of sugarcane bagasse (SCB) from the sugar-alcohol industry is considered a by-product with great potential for many bioproducts production. This work had as objective to verify the performance of sugarcane bagasse hemicellulosic hydrolysate (SCBHH) as source of sugars for enzymatic or in vitro xylitol production. For this purpose, xylitol enzymatic production was evaluated using different concentrations of treated SCBHH in the commercial reaction media. The weak acid hydrolysis of SCB provided a hydrolysate with 18 g L−1 and 6 g L−1 of xylose and glucose, respectively. Considering the reactions, changes at xylose–xylitol conversion efficiency and volumetric productivity in xylitol were not observed for the control experiment and using 20 and 40% v.v−1 of SCBHH in the reaction media. The conversion efficiency achieved 100% in all the experiments tested. The results showed that treated SCBHH is suitable as xylose and glucose source for the enzymatic xylitol production and that this process has potential as an alternative for traditional xylitol production ways. [Copyright &y& Elsevier]

Mycelium growth rates, biomass concentration (estimated as glucosamine content) and laccase and endoglucanase secretion were monitored during solid state fermentation (SSF) of wheat straw (WS), reed grass (RG) and bean stalk (BS) residues by Lentinula edodes strains 119, 121, and 122. In a first experiment, these strains were subjected to screening regarding their growth rates and biomass yield, where strain 121 proved to be the fastest colonizer. However, the greater biomass yield at the end of colonization was demonstrated by strain 122 on BS (465.93 mg g d.w.). In a second experiment, growth characters, as well as endoglucanase and laccase production patterns of the selected strains 121 and 122 were monitored at three intervals i.e., at 33, 66, and 100% of substrate colonization. BS furnished the highest endoglucanase production for strain 121, while RG for strain 122. A strain and substrate-dependent behaviour of the enzyme secretion was detected, with strain 122 presenting maximal endoglucanase activity in all substrates at the initial (33%) and final (100%) stages of colonization (0.64-0.90 and 0.79-0.97 U g respectively). However, in strain 121 the peak of endoglucanase production was detected in the early stages of colonization (at 33% on WS and at 66% on RG and BS). Laccase activity showed increased values (maxima on WS, 353.68 and 548.67 U g by strains 121 and 122, respectively) at 66% of colonization. Correlation analysis of growth data demonstrated negative relations between growth rate and biomass yield and between laccase and endoglucanase activities on WS and RG substrates fermented by strain 122. Finally, possible relations of growth parameters with nutritional constituents of the substrates were investigated. [ABSTRACT FROM AUTHOR]

Abstract: The ability of fungi to degrade lignocellulosic materials is due to their highly efficient enzymatic system. Fungi have two types of extracellular enzymatic systems; the hydrolytic system, which produces hydrolases that are responsible for polysaccharide degradation and a unique oxidative and extracellular ligninolytic system, which degrades lignin and opens phenyl rings. Lignocellulosic residues from wood, grass, agricultural, forestry wastes and municipal solid wastes are particularly abundant in nature and have a potential for bioconversion. Accumulation of lignocellulosic materials in large quantities in places where agricultural residues present a disposal problem results not only in deterioration of the environment but also in loss of potentially valuable material that can be used in paper manufacture, biomass fuel production, composting, human and animal feed among others. Several novel markets for lignocellulosic residues have been identified recently. The use of fungi in low cost bioremediation projects might be attractive given their lignocellulose hydrolysis enzyme machinery. [Copyright &y& Elsevier]

In this paper, integration possibilities for production of biodiesel and bioethanol using a single source of biomass as a feedstock (oil palm) were explored through process simulation. The oil extracted from Fresh Fruit Bunches was considered as the feedstock for biodiesel production. An extractive reaction process is proposed for transesterification reaction using in situ produced ethanol, which is obtained from two types of lignocellulosic residues of palm industry (Empty Fruit Bunches and Palm Press Fiber). Several ways of integration were analyzed. The integration of material flows between ethanol and biodiesel production lines allowed a reduction in unit energy costs down to 3.4%, whereas the material and energy integration leaded to 39.8% decrease of those costs. The proposed integrated configuration is an important option when the technology for ethanol production from biomass reaches such a degree of maturity that its production costs be comparable with those of grain or cane ethanol. [Copyright &y& Elsevier]

Abstract: The purpose of the present work was to evaluate the possibility of converting recycled paper sludge (RPS), an industrial residue stream with strong environmental impact, into valuable products. The approach used was based on the enzymatic conversion of major sludge components (cellulose and xylan) and the simultaneous (simultaneous saccharification and fermentation—SSF) or sequential (separate hydrolysis and fermentation—SHF) fermentation of the resulting sugars to ethanol. In the enzymatic hydrolysis step using Celluclast® 1.5L supplemented with Novozym® 188, a degree of saccharification of 100% was achieved. In relation to ethanol production using the yeast Pichia stipitis CBS 5773, SHF and SSF process efficiencies were compared. A slightly higher conversion yield was attained on SHF, corresponding to an ethanol concentration of 19.6gL−1, but 179h were needed. The SSF process was completed after 48h of incubation allowing the production of 18.6gL−1 of ethanol from 178.6gL−1 of dried RPS, corresponding to an overall conversion yield of 51% of the available carbohydrates on the initial substrate. These results demonstrate that the biological conversion of sludge to ethanol is efficient even with no pre-treatment or substrate supplementation. [Copyright &y& Elsevier]

The use of lignocelulosic residues as a source for ethanol production can offer an interesting alternative for diminishes the situation of transport sector. This work presents the main advantages of this process, and also the barriers that limiting the use of biocombustibles at higher scales. [ABSTRACT FROM AUTHOR]

[Display omitted] • Wheat straw-based itaconic acid is a promising alternative in biorefinery approach. • Pretreatment and fermentation stages account for the largest environmental burdens. • A renewable electricity has a significant influence on the environmental profile. This study performs the environmental assessment of itaconic acid (IA) production from wheat straw. The Life Cycle Assessment (LCA) methodology is used to determine the environmental hotspots, considering impact categories such as Global Warming (GW), Fossil Resource Scarcity (FRS), Water Consumption (WC), among others. A sensitivity analysis was performed considering an optimization of the steam explosion process and 100% renewable energy. Results report an impact of about 14.33 kg CO 2 eq in GW, 4.15 kg of oil eq in FRS, for each kg of IA produced for the baseline scenario. Moreover, the pretreatment and fermentation stages constitute hotspots of the IA production. In addition, using a renewable energy source in production would reduce the impact by 82% in GW, 71% in PM and 82% in FRS categories. The optimization of the steam explosion process presents a better performance in GW and FRS but also lies in an increase in WC. [ABSTRACT FROM AUTHOR]

[Display omitted] • Various agricultural wastes are potential substrates for PHA production. • Proper fermentation conditions and strategies promotes the PHA production. • Bioprocess kinetic parameters reflect the level of cell growth and PHA synthesis. • The circular approach of PHA production expands the application value of PHAs. • The adaptability of strains to different substrates is crucial to PHA synthesis. Polyhydroxyalkanoates are biopolymers produced by microbial fermentation. They have excellent biodegradability and biocompatibility, which are regarded as promising substitutes for traditional plastics in various production and application fields. This review details the research progress in PHA production from lignocellulosic crop residues, lipid-type agricultural wastes, and other agro-industrial wastes such as molasses and whey. The effective use of agricultural waste can further reduce the cost of PHA production while avoiding competition between industrial production and food. The latest information on fermentation parameter optimization, fermentation strategies, kinetic studies, and circular approach has also been discussed. This review aims to analyze the crucial process of the PHA production from agricultural wastes to provide support and reference for further scale-up and industrial production. [ABSTRACT FROM AUTHOR]

Pretreatment and codigestion are proven to be effective strategies for the enhancement of the anaerobic digestion of lignocellulosic residues. The purpose of this study is to evaluate the effects of pretreatment and codigestion on methane production and the hydrolysis rate in the anaerobic digestion of agricultural wastes (AWs). Thermal and different thermochemical pretreatments were applied on AWs. Sewage sludge (SS) was selected as a cosubstrate. Biochemical methane potential tests were performed by mixing SS with raw and pretreated AWs at different mixing ratios. Hydrolysis rates were estimated by the best fit obtained with the first-order kinetic model. As a result of the experimental and kinetic studies, the best strategy was determined to be thermochemical pretreatment with sodium hydroxide (NaOH). This strategy resulted in a maximum enhancement in the anaerobic digestion of AWs, a 56% increase in methane production, an 81.90% increase in the hydrolysis rate and a 79.63% decrease in the technical digestion time compared to raw AWs. On the other hand, anaerobic codigestion (AcoD) with SS was determined to be ineffective when it came to the enhancement of methane production and the hydrolysis rate. The most suitable mixing ratio was determined to be 80:20 (Aws/SS) for the AcoD of the studied AWs with SS in order to obtain the highest possible methane production without any antagonistic effect. [ABSTRACT FROM AUTHOR]

• Butyric acid from lignocellulosic feedstock is a promising biochemical alternative. • The environmental impacts of butyric acid production were assessed. • Steam and electricity are the most polluting processes. • Sensitivity analysis was performed using renewable energy and alternative feedstock. • The change in the type of electricity has a great influence on the results. Butyric acid is a valuable chemical that can be produced from oil or renewable feedstocks. However, due to technological advantages, it is currently synthesised at an industrial level by chemical synthesis. In view of the environmental concerns, attempts to produce butyric acid from renewable raw materials via microbial fermentation have been carried out. One possible route is the production of butyric acid from lignocellulosic feedstocks. This study aims to investigate the environmental profile of butyric acid production from wheat straw. The Life Cycle Assessment (LCA) methodology was applied considering two product formulations: butyric acid in combination with acetic acid (BA1) and butyric acid with high purity (BA2). The functional unit (FU) considered is 1 kg of BA1 and BA2. A sensitivity analysis was performed by considering 100 % renewable energy and using sugar beet pulp and maize stover as alternative lignocellulosic raw materials. The figures show that, when it comes to identify the hotspots of the process, the production of steam, electricity and cellulase cocktail were the main processes with the highest environmental shares for both products, BA1 and BA2. The best environmental profile corresponded to BA1 due to the lower amount of energy and inputs required. The results of the sensitivity analysis reveal that the use of 100 % renewable energy in the production process would significantly reduce the environmental burdens. On the other hand, the use of beet pulp or maize stover as alternatives to wheat straw did not significantly change the global environmental results. This paper shows the importance of applying the LCA methodology to identify possible process improvement alternatives at an early stage of product development. [ABSTRACT FROM AUTHOR]

The use of agroindustrial waste for chemicals, biofuels and food ingredients production has been studied considering limitations of natural resources. Therefore, sugarcane bagasse was studied to produce arabinoxylan, xylanases, xylooligosaccharides and lignocellulose by the improvement of some technologies. A comparison of two methods of extraction of arabinoxylan was performed. Arabinoxylan was obtained in a soluble fraction in a better extraction by KOH method with higher yield (72.1%) and efficiency (84%) than H 2 O 2 method, which only produced 64.9 and 43.3%, respectively. Lignocellulose was obtained after filtration, as the solid fraction, representing 66.2% (KOH) and 78.8% (H 2 O 2 method) of the total biomass. The endoxylanase was produced by Aspergillus fumigatus CCT7732 in submerged fermentation with bagasse culture medium reaching 40.2 U/mL in optimal conditions, pH 5.0 and 31.5 °C. In addition, NH 4 H 2 PO 4 was efficient as phosphorus and nitrogen sources for xylanases production in the culture, when the more expensive salts K 2 HPO 4 and KH 2 PO 4 were replaced. An enzymatic hydrolysis of arabinoxylan in Xylooligosaccharides (XOS) by xylanases of A. fumigatus resulted in 3.3% (m/v) XOS, 46.9% yield using 7% arabinoxylan, 350 U/g of xylanases at 50 °C in 48 h. These methods provided a prebiotic XOS since mainly xylobiose and xylotriose were produced with potential applications for food and feed. The set of chemical and biological methods applied in bagasse indicated that these methods should be evaluated in scale up of an integrated biosystem including economic studies for industrial purposes. • Arabinoxylan was better extracted from bagasse by KOH method than peroxide. • Alkaline method also can be used to obtain lignocellulose fraction from bagasse. • High level of xylanases can be obtained by A. fumigatus culture using bagasse. • NH 4 H 2 PO 4 can be less expensive than other nitrogen salts for the culture. • High level of XOS was produced with optimized xylanases hydrolyses of arabinoxylan. [ABSTRACT FROM AUTHOR]