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Cellulosic ethanol is regarded as a perfect additive for petrol fuels for global carbon neutralization. As bioethanol conversion requires strong biomass pretreatment and overpriced enzymatic hydrolysis, it is increasingly considered in the exploration of biomass processes with fewer chemicals for cost-effective biofuels and value-added bioproducts. In this study, we performed optimal liquid-hot-water pretreatment (190 °C for 10 min) co-supplied with 4% FeCl3 to achieve the near-complete biomass enzymatic saccharification of desirable corn stalk for high bioethanol production, and all the enzyme-undigestible lignocellulose residues were then examined as active biosorbents for high Cd adsorption. Furthermore, by incubating Trichoderma reesei with the desired corn stalk co-supplied with 0.05% FeCl3 for the secretion of lignocellulose-degradation enzymes in vivo, we examined five secreted enzyme activities elevated by 1.3–3.0-fold in vitro, compared to the control without FeCl3 supplementation. After further supplying 1:2 (w/w) FeCl3 into the T. reesei-undigested lignocellulose residue for the thermal-carbonization process, we generated highly porous carbon with specific electroconductivity raised by 3–12-fold for the supercapacitor. Therefore, this work demonstrates that FeCl3 can act as a universal catalyst for the full-chain enhancement of biological, biochemical, and chemical conversions of lignocellulose substrates, providing a green-like strategy for low-cost biofuels and high-value bioproducts. [ABSTRACT FROM AUTHOR]

Bamboo is a fast-growing perennial plant rich at lignocellulose convertible for biofuels and biochemical production. Despite various physical and chemical pretreatments have been implemented for bamboo biomass utilization, it becomes essential to explore optimal technology for complete biomass saccharification to maximize bioethanol production in the desirable bamboo substrates. In this study, the steam explosion followed with optimized green-liquor pretreatments were conducted in different-year-old bamboo samples using response surface methodology. Compared to the older samples, the one-year-old bamboo (PhY1) showed a complete biomass enzymatic saccharification with hexoses yield of 100.0% (% cellulose), leading to the highest bioethanol yield of 20.3% (% dry biomass) achieved among all previously-reported bamboo processes. Notably, those combined pretreatments could not only cause an effective co-extraction of hemicellulose-lignin complexes, but also distinctively modify major wall polymer features (cellulose DP and accessibility, hemicellulosic Xyl/Ara and lignin S/G) for significantly reduced lignocellulose recalcitrance, which should lead to an integrated enhancement to biomass enzymatic saccharification in the PhY1 bamboo sample. Therefore, this study has demonstrated a powerful strategy for a green-like biomass process, providing an applicable technology to achieve maximum bioethanol production in bamboo and other lignin-rich bioenergy crops. • Steam explosion followed by optimal green liquor pretreatment performed in bamboo. • Complete saccharification and maximum bioethanol achieved in one-year-old bamboo. • Effective extraction of hemicellulose-lignin complexes by combined pretreatments. • Reduced lignocellulose recalcitrance from combined pretreatments with bamboo. • A green-like biomass process to achieve maximum bioethanol in bamboo and beyond. [ABSTRACT FROM AUTHOR]

Genetic modification of plant cell walls has been posed to reduce lignocellulose recalcitrance for enhancing biomass saccharification. Since cellulose synthase (CESA) gene was first identified, several dozen CESA mutants have been reported, but almost all mutants exhibit the defective phenotypes in plant growth and development. In this study, the rice (Oryza sativa) Osfc16 mutant with substitutions (W481C, P482S) at P-CR conserved site in CESA9 shows a slightly affected plant growth and higher biomass yield by 25%-41% compared with wild type (Nipponbare, a japonica variety). Chemical and ultrastructural analyses indicate that Osfc16 has a significantly reduced cellulose crystallinity (CrI) and thinner secondary cell walls compared with wild type. CESA co-IP detection, together with implementations of a proteasome inhibitor (MG132) and two distinct cellulose inhibitors (Calcofluor, CGA), shows that CESA9 mutation could affect integrity of CESA4/7/9 complexes, which may lead to rapid CESA proteasome degradation for low-DP cellulose biosynthesis. These may reduce cellulose CrI, which improves plant lodging resistance, a major and integrated agronomic trait on plant growth and grain production, and enhances biomass enzymatic saccharification by up to 2.3-fold and ethanol productivity by 34%-42%. This study has for the first time reported a direct modification for the low-DP cellulose production that has broad applications in biomass industries. [ABSTRACT FROM AUTHOR]

Bioenergy crops provide enormous renewable biomass resources convertible for biofuel production, but lignocellulose recalcitrance fundamentally determines its enzymatic saccharification at high cost and low efficiency. In this study, total 30 diverse Miscanthus lignocellulose substrates were incubated with T. reesei strain to secret lignocellulose-degradation enzymes, and their major wall polymers features (cellulose crystallinity, hemicellulose arabinose and lignin H-monomer) were meanwhile examined with distinct impacts on the enzyme activities. Using characteristic Miscanthus (Msi62) de-lignin residue as inducing substrate with the reesei strain, this study detected that the Msi62-induced enzymes were of consistently higher enhancements on enzymatic saccharification of various lignocellulose residues examined in 17 grassy and woody bioenergy crops, particularly for the hemicellulose hydrolyses, compared to other two reesei -secreted cellulases and three commercial enzymes. Notably, based on SDS-gel protein separation profiling and LC-MS/MS analysis, the Msi62-induced enzymes consist of distinct cellulases (CBHI, BG, EGII) compositions and high-activity xylanases. Therefore, this study has demonstrated an applicable approach to achieve the optimal cellulases and xylanases cocktails that enable for low-costly and high-efficient enzymatic saccharification of diverse lignocellulose sources, providing a potential strategy for large-scale biofuel production in all major bioenergy crops. • Miscanthus lignocellulose features affect T. reesei -secreted enzymes activities. • Msi62 de-lignin residue induces reesei to secret distinct cellulases and xylanases. • Msi62-induced enzymes are of the highest activity for hemicelluloses hydrolyses. • Msi62-induced enzyme enable for high saccharification of all bioenergy crops. • A potential strategy for efficient biomass saccharification and biofuel production. [ABSTRACT FROM AUTHOR]

• Silwet L-77 specifically enhances direct enzymatic hydrolysis of Miscanthus straw. • Silwet L-77 is consistent for high ethanol conversion rates in diverse substrates. • Surfactants distinctively block lignin for efficient enzymatic saccharification. • Steam explosion and mild chemical applicable for complete biomass saccharification. • A low-cost and high-efficient strategy for bioethanol production in bioenergy crops. Miscanthus is a leading bioenergy crop that represents an enormous lignocellulose resource for biofuels and bioproducts. However, as lignocellulose recalcitrance leads to financially inviable bioethanol production and the potential of secondary wastes into the environment, it becomes crucial to explore green-like and cost-effective biomass processing technologies. To address these issues, low doses of chemical surfactants have been added to enhance biomass enzymatic hydrolysis and bioethanol conversion, but much remains unknown about the mechanism of enhancement. For first time, in this study, a novel chemical surfactant (1% Silwet L-77) was applied to enhance the enzymatic hydrolysis of raw Miscanthus straw, and 40% cellulose digestion was achieved, which is 1.2- and 4.5-fold higher than that of two well-known surfactants (PEG-4000 and Tween-80), respectively. Using lignocellulose substrates obtained from Miscanthus biomass samples that were pretreated by green-like steam explosion followed by mild chemical (NaOH or H 2 SO 4) pretreatments, supplementation with the three surfactants led to significantly enhanced enzymatic saccharification. The 2% Tween-80 supply resulted in a hexose yield of 99% (% cellulose) from enzymatic hydrolysis, followed by 95% with 0.5% PEG-4000 and 71% with 1% Silwet L-77. Despite the slightly lower hexose yield, Silwet L-77 resulted in consistently higher sugar-ethanol conversion rates in all lignocellulose substrates examined. Furthermore, based on the enzyme profiling of mixed cellulase adsorption on lignocellulose and the chemical analysis of wall polymer features and lignocellulose accessibility, this study proposed multiple hypothetical models to interpret the distinct enhancement roles of three surfactants in the enzymatic hydrolyses of diverse lignocellulose substrates. These models also provide a powerful strategy for low-cost bioethanol production with the potential for high-value bioproducts by using desirable surfactants in Miscanthus and other bioenergy crops. [ABSTRACT FROM AUTHOR]

Miscanthus is a leading bioenergy crop with enormous biomass resource convertible into bioethanol and biochemicals. However, lignocellulose recalcitrance basically causes costly bioethanol production with potential secondary pollution to the environment. In this study, the green liquor (mixed sodium carbonate and sodium sulfide) pretreatments were optimized using response surface methodological modeling for enhancing biomass saccharification and delignification in Miscanthus. By comparison, the optimal saccharification approach led to relatively higher hexose yield of 87% (% cellulose) for bioethanol yield of 17.1% (% dry matter) with the sugar-ethanol conversion rate at 98%, whereas the optimal delignification approach could achieve the highest delignification rate at 93% potential for lignin-derived biofuel or value-added biochemicals. Notably, those two optimized pretreatments could distinctively extract hemicellulose-lignin complex and altered wall polymer features, leading to much increased cellulose accessibility for efficient biomass enzymatic hydrolysis. Exceptionally, the optimal delignification led to decreased biomass porosity accountable for relatively lower hexose yield, suggesting that its cellulose microfibrils may be aggregated from excessive non-cellulosic polymers extraction. Hence, this study has demonstrated two optional strategies for green-like and cost-effective biofuels and biochemical production in Miscanthus and other bioenergy crops. Image 1 • Green liquor pretreatment was optimized for saccharification and delignification. • Optimal saccharification approach led to higher hexose yield at 87% (% cellulose). • The highest delignification rate was so far obtained at 93% for advanced biofuels. • Two pretreatments distinctively altered wall polymer features and inter-linkages. • Two optional strategies for green-like biofuel production in bioenergy Miscanthus. [ABSTRACT FROM AUTHOR]

Miscanthus is a leading bioenergy crop and rice provides enormous biomass for biofuels. Using Calcofluor White staining, this work in situ observed an initial lignocellulose hydrolysis in two distinct Miscanthus accessions, rice cultivar (NPB), and Osfc16 mutant after mild chemical pretreatments. In comparison, the M. sin and Osfc16 respectively exhibited weak Calcofluor fluorescence compared to the M. sac and NPB during enzymatic hydrolysis, consistent with the high biomass saccharification detected in vitro . Using xyloglucan-directed monoclonal antibodies (mAbs), xyloglucan deconstruction was observed from initial cellulose hydrolysis, whereas the M. sin and Osfc16 exhibited relatively strong immunolabeling using xylan-directed mAb, confirming previous findings of xylan positive impacts on biomass saccharification. Furthermore, the M. sin showed quick disappearance of RG-I immunolabeling with varied HG labelings between acid and alkali pretreatments. Hence, this study demonstrated a quick approach to explore wall polymer distinct deconstruction for enhanced biomass saccharification under chemical pretreatment in bioenergy crops. [ABSTRACT FROM AUTHOR]

In this study, a combined pretreatment was performed in four wheat accessions using steam explosion followed with different concentrations of H 2 SO 4 or NaOH, leading to increased hexoses yields by 3–6 folds from enzymatic hydrolysis. Further co-supplied with 1% Tween-80, Talq90 and Talq16 accessions exhibited an almost complete enzymatic saccharification of steam-exploded (SE) residues after 0.5% H 2 SO 4 or 1% NaOH pretreatment, with the highest bioethanol yields at 18.5%–19.4%, compared with previous reports about wheat bioethanol yields at 11%–17% obtained under relatively strong pretreatment conditions. Furthermore, chemical analysis indicated that much enhanced saccharification in Talq90 and Talq16 may be partially due to their relatively low cellulose CrI and DP values and high hemicellulose Ara and H-monomer levels in raw materials and SE residues. Hence, this study has not only demonstrated a mild pretreatment technology for a complete saccharification, but it has also obtained the high ethanol production in desirable wheat accessions. [ABSTRACT FROM AUTHOR]

In this study, two rice cultivars were collected from experimental fields with seven nitrogen fertilizer treatments. All biomass samples contained significantly increased cellulose contents and reduced silica levels, with variable amounts of hemicellulose and lignin from different nitrogen treatments. Under chemical (NaOH, CaO, H 2 SO 4 ) and physical (hot water) pretreatments, biomass samples exhibited much enhanced hexoses yields from enzymatic hydrolysis, with high bioethanol production from yeast fermentation. Notably, both degree of polymerization (DP) of cellulose and xylose/arabinose (Xyl/Ara) ratio of hemicellulose were reduced in biomass residues, whereas other wall polymer features (cellulose crystallinity and monolignol proportion) were variable. Integrative analysis indicated that cellulose DP, hemicellulosic Xyl/Ara and silica are the major factors that significantly affect cellulose crystallinity and biomass saccharification. Hence, this study has demonstrated that nitrogen fertilizer supply could largely enhance biomass saccharification in rice cultivars, mainly by reducing cellulose DP, hemicellulosic Xyl/Ara and silica in cell walls. [ABSTRACT FROM AUTHOR]

In this study, total ten Miscanthus accessions exhibited diverse cell wall compositions, leading to largely varied hexoses yields at 17%–40% (% cellulose) released from direct enzymatic hydrolysis of steam-exploded (SE) residues. Further supplied with 2% Tween-80 into the enzymatic digestion, the Mis7 accession showed the higher hexose yield by 14.8-fold than that of raw material, whereas the Mis10 had the highest hexoses yield at 77% among ten Miscanthus accessions. Significantly, this study identified four wall polymer features that negatively affect biomass saccharification as p < 0.05 or 0.01 in the SE residues, including cellulose DP, Xyl and Ara of hemicellulose, and S-monomer of lignin. Based on Simons’ stain, the SE porosity (defined by DY/DB) was examined to be the unique positive factor on biomass enzymatic digestion. Hence, this study provides the potential strategy to enhance biomass saccharification using optimal biomass process technology and related genetic breeding in Miscanthus and beyond. [ABSTRACT FROM AUTHOR]

In this study, eight physical and chemical pretreatments were compared in terms of their enhancements on biomass enzymatic saccharification in reed. Despite 8% NaOH pretreatment could result in 100% biomass enzymatic digestion while co-supplied with 1% Tween-80, it only produced bioethanol at 10% (% dry matter). By comparison, 10% CaO pretreatment with Tween-80 is a relatively low-cost biomass conversion with ethanol yield at 12%. Notably, the steam-explosion pretreatment with 1% Tween-80 could cause a complete biomass enzymatic hydrolysis with bioethanol yield at 17%. The sequential 5% CaO pretreatment with the steam-exploded residues could lead to the highest ethanol yield at 19% with an almost complete sugar–ethanol conversion rate. Due to much low-DP cellulose and less noncellulosic polymers (lignin, hemicelluloses) that increase biomass surfaces, the steam-exploded residues were specifically effective for Tween-80 either to block lignin absorbing with cellulases or to disassociate hemicelluloses, leading to an efficient lignocellulose enzymatic digestion. Compared with previously reported pretreatments in other C4-grasses ( Miscanthus , corn, sweet sorghum, switchgrass), to our knowledge, this study has therefore provided three more applicable approaches for high ethanol production with relatively low cost, less contaminate release and efficient biomass conversion rates in reed. [ABSTRACT FROM AUTHOR]

In this study, steam explosion pretreatment was performed in cotton stalks, leading to 5–6 folds enhancements on biomass enzymatic saccharification distinctive in Gossypium barbadense and Gossypium hirsutum species. Sequential 1% H 2 SO 4 pretreatment could further increase biomass digestibility of the steam-exploded stalks, and also cause the highest sugar–ethanol conversion rates probably by releasing less inhibitor to yeast fermentation. By comparison, extremely high concentration alkali (16% NaOH) pretreatment with raw stalks resulted in the highest hexoses yields, but it had the lowest sugar–ethanol conversion rates. Characterization of wall polymer features indicated that biomass saccharification was enhanced with steam explosion by largely reducing cellulose DP and extracting hemicelluloses. It also showed that cellulose crystallinity and arabinose substitution degree of xylans were the major factors on biomass digestibility in cotton stalks. Hence, this study has provided the insights into cell wall modification and biomass process technology in cotton stalks and beyond. [ABSTRACT FROM AUTHOR]

Pectin is a minor wall polysaccharide with potential applications for bioproducts. Despite the application of specific plants and biomass-based sorbents for environmental remediation, little has been reported about characteristic roles of pectin. Using the natural rice mutant (Osfc16) treated with Cd, this study explored that pectin could predominately enhance Cd accumulation with lignocellulose, mainly due to remarkably raised uronic acids deposition. The Cd-treatment further reduced lignocellulose recalcitrance for significantly enhanced biomass saccharification and bioethanol production along with almost complete Cd release. Using all remaining fermentation rice residues that are of typical ribbon-structure and large surface, this study generated novel biosorbents by optimal chemical oxidation with the pectin extraction from citrus peels, and examined consistently raised Cd and methylene blue (MB) adsorption capacities. Therefore, this work has proposed a mechanism model about multiple pectin enrichment roles for Cd and MB removals in agricultural and industry locations with full lignocellulose utilization towards bioethanol production. [Display omitted] [ABSTRACT FROM AUTHOR]

Improving biomass enzymatic saccharification is effective for crop straw utilization, whereas phytoremediation is efficient for trace metal elimination from polluted agricultural soil. Here, we found that the green proteins extracted from Amaranthus leaf tissue could act as active biosurfactant to remarkably enhance lignocellulose enzymatic saccharification for high bioethanol production examined in eight grassy and woody plants after mild chemical and green-like pretreatments were performed. Notably, this study estimated that total green proteins supply collected from one-hectare-land Amaranth plants could even lead to additional 6400–12,400 tons of bioethanol, being over 10-fold bioethanol yield higher than those of soybean seed proteins and chemical surfactant. Meanwhile, the Amaranth green proteins were characterized as a dominated biosorbent for multiple trace metals (Cd, Pb, As) adsorption, being 2.9–6 folds higher than those of its lignocellulose. The Amaranth plants were also assessed to accumulate much more trace metals than all other plants as previously examined from large-scale contaminated soils. Furthermore, the Amaranth green proteins not only effectively block lignin to release active cellulases for the mostly enhanced biomass hydrolyzes, but also efficiently involve in multiple chemical bindings with Cd, which should thus address critical issues of high-costly biomass waste utilization and low-efficient trace metal remediation. ga1 • Amaranth green proteins act as universal biosurfactant for biomass lignin blocking. • Enhanced saccharification of diverse biomass residues by green proteins supply. • Green proteins paly a dominated biosorbent role for three trace metals adsorption. • Amaranth plants accumulate much more trace metals than all other plants from lands. • Green proteins involve in multiple chemical interlinking with Cd for adsorption. [ABSTRACT FROM AUTHOR]