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The enzymatic synthesis of xylose fatty acid esters was carried out in two steps: hydrolysis of degummed soybean oil (DSO) and esterification of the produced and purified free fatty acids (FFA) with xylose. Different lipases immobilized on a hydrophobic support were evaluated in the hydrolysis of DSO and an experimental design was used to optimize the reaction. Eversa® Transform 2.0 (EV-Purolite) yielded 93% conversion after 6 h using biocatalyst load of 6.53 wt%, water/oil mass ratio of 5.5 and temperature of 48.4 °C. High operational stability for EV-Purolite was found using a sequential batch strategy and the possibility of concentrating glycerol. In the esterification stage, lipase from Thermomyces lanuginosus (TLL-Purolite) and lipase B from Candida antarctica showed better performance than lipase from porcine pancreas and EV-Purolite. About 17% of FFAs (0.85 molecules of FAA per xylose molecule) was consumed using an enzyme load of 5 wt% of TLL-Purolite and FFA/xylose molar ratio of 5. Sequential esterification batches showed low operational stability of TTL-Purolite due to the desorption of TLL from the support. The final mixture of the reaction medium containing xylose fatty acid esters showed emulsifying properties similar to those of commercial surfactant. [Display omitted] • Xylose fatty acid esters production by degummed soybean oil hydroesterification. • Hydrolysis catalyzed by immobilized Eversa produced 92% of FFAs after 6 h. • Reuse of immobilized Eversa for five consecutive 3 h-batches of hydrolysis. • Modification of 85% xylose as monoester using immobilized TLL. • Xylose esters showed emulsifying properties similar to commercial surfactants. [ABSTRACT FROM AUTHOR]

Objective: New characterized carbohydrate-active enzymes are needed for use as tools to discriminate complex carbohydrate structural features. Fungal glycoside hydrolase family 3 (GH3) β-xylosidases have been shown to be useful for the structural elucidation of glucuronic acid (GlcA) and arabinofuranose (Araf) substituted oligoxylosides. A homolog of these GH3 fungal enzymes from the bacterium Segatella baroniae (basonym Prevotella bryantii), Xyl3C, has been previously characterized, but those studies did not address important functional specificity features. In an interest to utilize this enzyme for laboratory methods intended to discriminate the structure of the non-reducing terminus of substituted xylooligosaccharides, we have further characterized this GH3 xylosidase. Results: In addition to verification of basic functional characteristics of this xylosidase we have determined its mode of action as it relates to non-reducing end xylose release from GlcA and Araf substituted oligoxylosides. Xyl3C cleaves xylose from the non-reducing terminus of β-1,4-xylan until occurrence of a penultimate substituted xylose. If this substitution is O2 linked, then Xyl3C removes the non-reducing xylose to leave the substituted xylose as the new non-reducing terminus. However, if the substitution is O3 linked, Xyl3C does not hydrolyze, thus leaving the substitution one-xylose (penultimate) from the non-reducing terminus. Hence, Xyl3C enables discrimination between O2 and O3 linked substitutions on the xylose penultimate to the non-reducing end. These findings are contrasted using a homologous enzyme also from S. baroniae, Xyl3B, which is found to yield a penultimate substituted nonreducing terminus regardless of which GlcA or Araf substitution exists. [ABSTRACT FROM AUTHOR]

In order to obtain high yields of chemicals and fuels from biomass, feedstocks need to be selected that contain high amounts of glucose, xylose, or lignin, depending on the end product. The first objective of this study was to evaluate the biomass composition of 20 samples from 11 broadleaf and grass crop species grown at two distinct sites in Montana. Another objective was to investigate the influence of growing location and seed type to determine which cultivars may be best for renewable chemical production in the northern Great Plains. There was a significant effect due to the growing location as the biomass samples from the site that had higher precipitation exhibited a significantly higher acid-insoluble lignin (23.8%) content compared to the biomass samples from the lower precipitation site (20.0%). Additionally, the 357 napus had a significantly higher amount of glucose (1.8% more) and acid-soluble lignin (0.2% more) than compared to the 940 napus both grown at the Froid site that may be attributed to genetic modifications. In terms of sugar content for potential upgrading, the grasses had significantly more glucose (36.1% total), xylose (24.3%), and arabinose (2.3%) than the Brassicaceae biomasses, but the lignin content was not significantly different. Switchgrass, in particular, had the highest total sugar content of close to 70 wt%. Understanding the impact of growing location on biomass composition is an important consideration for optimizing biomass utilization strategies and developing sustainable bioenergy production systems. [ABSTRACT FROM AUTHOR]

Serratia marcescens is utilized as a significant enterobacteria in the production of various high‐value secondary metabolites. Acetoin serves as a crucial foundational compound of development and finds application in a broad range of fields. Furthermore, S. marcescens HBQA‐7 is capable of utilizing xylose as its exclusive carbon source for acetoin production. The objective of this study was to utilize a constitutive promoter screening strategy to enhance both xylose utilization and acetoin production in S. marcescens HBQA‐7. By utilizing RNA‐seq, we identified the endogenous constitutive promoter P6 that is the most robust, which facilitated the overexpression of the sugar transporter protein GlfL445I, α‐acetyl lactate synthase, and α‐acetyl lactate decarboxylase, respectively. The resultant recombinant strains exhibited enhanced xylose utilization rates and acetoin yields. Subsequently, a recombinant plasmid, denoted as pBBR1MCS‐P6‐glfL445IalsSalsD, was constructed, simultaneously expressing the aforementioned three genes. The resulting recombinant strain, designated as S3, demonstrated a 1.89‐fold boost in xylose consumption rate compared with the original strain during shake flask fermentation. resulting in the accumulation of 7.14 g/L acetoin in the final fermentation medium. Subsequently, in a 5 L fermenter setup, the acetoin yield reached 48.75 g/L, corresponding to a xylose‐to‐acetoin conversion yield of 0.375 g/g. [ABSTRACT FROM AUTHOR]

BACKGROUND: Glycation is a green processing technology. Based on our previous studies, glycation with l‐arabinose and xylose was beneficial to enhance the texture properties of silver carp mince (SCM) gels. However, the possible enhancement mechanism remained unclear. Therefore, in this study, SCM gels with different types of reducing sugar (glucose, l‐arabinose, and xylose) were prepared based on our previous study. The possible mechanism of texture enhancement of SCM gels was analyzed by investigating the changes in water distribution, protein structures, and microstructure in the gel system. RESULTS: The glycation of l‐arabinose and xylose enhanced the hardness, cohesiveness, chewiness, and resilience of SCM gels. Hardness increased from 1883.04 (control group) to 3624.54 (l‐arabinose group) and 4348.18 (xylose group). Low‐field nuclear magnetic resonance (LF‐NMR) showed that glycation promoted the tight binding of immobilized water to proteins. Raman spectroscopic analysis showed that glycation increased the surface hydrophobicity and promoted the formation of disulfide bonds. Scanning electron microscopy (SEM) showed that glycation promoted the formation of uniform and dense three‐dimensional network structure in SCM gels. CONCLUSION: In summary, glycation enhanced the binding ability of immobilized water to proteins, improved the surface hydrophobicity, promoted the formation of disulfide bonds, and led to a more uniform and dense gel network structure of proteins, thus enhancing the texture properties of SCM gels. This research provided a theoretical basis for a better understanding of the mechanism of the effect of glycation on the quality of gel products and also provided technical support for the application of l‐arabinose and xylose in new functional gel foods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOx) catalyzes the oxidation of D -glucose to D -glucono-1,5-lactone and has a wide range of applications in various industries. However, the strict substrate specificity of GOx hampers its application in the conversion of other abundant sugars such as D -xylose. In this study, the substrate preference of GOx from Aspergillus niger (AnGOx) was engineered using a semi-rational design approach. The mutant T110V/F414L exhibited a 5.7-fold increase in D -xylose oxidation activity compared to that of the wild-type enzyme, which was attributed to its enhanced affinity for the substrate. Molecular dynamics simulations indicated that the T110V and F414L mutations may mitigate the non-productive binding of D -xylose at the entrance of the substrate-binding pocket, and therefore, are beneficial for providing access of its C1 hydroxyl group to the catalytic residues. Moreover, the mutant simultaneously oxidized D -xylose and D -glucose in the corncob hydrolysate to the corresponding aldonic acids when coupled with catalase. These findings provide new insights into substrate recognition by GOx and offer a new method for the utilization of D -xylose from lignocellulosic feedstocks. [ABSTRACT FROM AUTHOR]

This study aims to utilize the microbial resources found within Laphet-so, a traditional fermented tea in Myanmar. A total of 18 isolates of thermotolerant yeasts were obtained from eight samples of Laphet-so collected from southern Shan state, Myanmar. All isolates demonstrated the tannin tolerance, and six isolates were resistant to 5% (w/v) tannin concentration. All 18 isolates were capable of carboxy-methyl cellulose (CMC) degrading, but only the isolate DK showed ethanol production at 45 °C noticed by gas formation. This ethanol producing yeast was identified to be Cyberlindnera rhodanensis based on the sequence analysis of the D1/D2 domain on rRNA gene. C. rhodanensis DK produced 1.70 ± 0.01 U of thermostable extracellular β-glucosidase when cultured at 37 °C for 24 h using 0.5% (w/v) CMC as a carbon source. The best two carbon sources for extracellular β-glucosidase production were found to be either xylose or xylan, with β-glucosidase activity of 3.07–3.08 U/mL when the yeast was cultivated in the yeast malt extract (YM) broth containing either 1% (w/v) xylose or xylan as a sole carbon source at 37 °C for 48 h. The optimal medium compositions for enzyme production predicted by Plackett–Burman design and central composite design (CCD) was composed of yeast extract 5.83 g/L, peptone 10.81 g/L and xylose 20.20 g/L, resulting in a production of 7.96 U/mL, while the medium composed (g/L) of yeast extract 5.79, peptone 13.68 and xylan 20.16 gave 9.45 ± 0.03 U/mL for 48 h cultivation at 37 °C. Crude β-glucosidase exhibited a remarkable stability of 100%, 88% and 75% stable for 3 h at 35, 45 and 55 °C, respectively. [ABSTRACT FROM AUTHOR]

Heterojunction photocatalysts receive significant interest due to their high performance and easy fabrication. An S-scheme heterojunction is developed on the basis of conventional type II heterojunctions, which can further promote charge separation and migration. In this work, a photocatalyst with a dual S-scheme heterojunction (denoted as C-s-ZIS/CN) is developed by the hybridization of CuInS2 quantum dot-sensitized ZnIn2S4 nanosheets and g-C3N4 nanosheets. CuInS2 quantum dot sensitization efficiently enhanced light absorption. Meanwhile, the unique charge migration pathway in the dual S-scheme heterojunction accelerated the separation and transfer of photogenerated carriers. The photocatalyst was innovatively employed in the simultaneous photocatalytic production of xylonic acid and CO. Under 10 W LED light irradiation (790 mW cm−2), the CO evolution rate reached a high of 228.94 μmol g−1 h−1. When a xenon lamp was employed, the CO evolution rate increased to 964.27 μmol g−1 h−1. Moreover, the optimal xylonic acid yield achieved was up to 58.56%. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenolysis of xylose to ethylene glycol (EG) and 1,2-propanediol (1,2-PG) is an important way for the high-value valorization of biomass. Herein, Ni-W/CeO2 catalysts prepared by incipient-wetness impregnation method were used for the hydrogenolysis of xylose to EG and 1,2-PG. Several characterizations such as X-ray diffraction (XRD), Transmission electron microscopy (TEM) and X-ray photoelectronic spectroscopy (XPS) were used to analyze the physicochemical properties of the catalysts. The effects of different Ni/W ratios and reaction conditions on the hydrogenolysis performance of the catalyst were investigated. The doping of W promoted the selective cleavage of C–C and C-O bonds of xylose, thus improved the yield of EG 1,2-PG. The doping of W can form interactions with Ni and increase the oxygen vacancy concentration of CeO2, which have a significant impact on the catalyst activity. When the Ni: W ratio is around 1:1, the catalyst has the best activity, and the total yield of diols can reach about 43.2%.. When xylan was used as the substrate, the total yield of diols can reach to 58.7%. The possible reaction mechanism of xylose hydrogenolysis was also discussed. This work developed a new catalyst system for the directional conversion of xylose to EG and 1,2-PG, which provided a new idea for the design of catalyst to converting lignocellulose, especially carbohydrate into high-value chemicals. Ni-W/CeO2 with different Ni/W ratio are efficient catalysts for hydrogenolysis of xylose to EG and 1,2-PG. [ABSTRACT FROM AUTHOR]

In this study, bacterial cellulose (BC) was obtained from Komagataeibacter xylinus S4 and characterized in detail. The effects of a various of carbon sources and media, different pH conditions, incubation temperatures, Surface area/Volume ratios, and incubation durations were determined for BC production. Considering the carbon types, the amount of BC production from high to low was realized as sucrose, fructose, mannitol, xylose, arabinose, and lactose. The highest BC amount (1.303 g/L) was achieved by combining M1A05P5 broth, 30 °C, 1.06 cm-1 Surface area/Volume ratio, pH 3.5 and 21 days. According to scanning electron microscope (SEM) analysis, the cellulose fibril diameters were 34.87-45.97 nm at pH 3.5 and 29.71-102.3 nm at pH 6.5 in M1A05P5. Also, TGA analysis exhibited that the weight loss of BC in the removal of water step initialized between 50 °C and 150 °C and the degradation step initialized between 215 °C and 228 °C. Finally, the electrical conductivity values of the BC samples were determined on the 27-137 °C temperature scale. It was observed that the conductivity was temperature dependent, and the conductivity increased exponentially as the temperature increased. In conclusion, the cellulose from K. xylinus S4 typically showed a semiconducting behavior. [ABSTRACT FROM AUTHOR]

The present work models the fermentation process parameters of the newly isolated, Meyerozyma caribbica CP02 for enhanced xylitol production and its fermentability study on rice straw hydrolysate. The study examined the impact of each of the process variables by one variable at a time optimization followed by statistical validation. Temperature of 32 °C, pH of 3.5, agitation of 200 rpm, 1.5% (v/v) inoculum, 80 gL−1 initial xylose was optimized. Subsequently, a sequential two-stage agitation approach was adopted for fermentation. At these optimized conditions, xylitol yield of 0.77 gg−1 and 0.64 gg−1 was achieved using media containing commercial and rice straw derived xylose, respectively. For scale up, in 3L batch bioreactor, the highest xylitol yield (0.63 gg−1) was attained at 72 h with rice straw hydrolysate media containing initial xylose (59.48 ± 0.82 gL−1) along with inhibitors (1.55 ± 0.10 gL−1 aliphatic acids, 0.0.048 ± 0.11 gL−1 furans, 0.64 ± 0.23 gL−1 total phenols). The results imply that even under circumstances characterized by an acidic pH and elevated initial xylose level, M. caribbica CP02, as an isolate, displays robustness and shows favorable fermentability of rice straw hydrolysate. Therefore, isolate CP02 has potential to be used in bio-refineries for high yield xylitol production with minimal hydrolysate processing requirements. [ABSTRACT FROM AUTHOR]

Corn cob is a major waste mass-produced in corn agriculture. Corn cob hydrolysate containing xylose, arabinose, and glucose is the hydrolysis product of corn cob. Herein, a recombinant Escherichia coli strain BT-10 was constructed to transform corn cob hydrolysate into 1,2,4-butanetriol, a platform substance with diversified applications. To eliminate catabolite repression and enhance NADPH supply for alcohol dehydrogenase YqhD catalyzed 1,2,4-butanetriol generation, ptsG encoding glucose transporter EIICBGlc and pgi encoding phosphoglucose isomerase were deleted. With four heterologous enzymes including xylose dehydrogenase, xylonolactonase, xylonate dehydratase, α-ketoacid decarboxylase and endogenous YqhD, E. coli BT-10 can produce 36.63 g/L 1,2,4-butanetriol with a productivity of 1.14 g/[L·h] using xylose as substrate. When corn cob hydrolysate was used as the substrate, 43.4 g/L 1,2,4-butanetriol was generated with a productivity of 1.09 g/[L·h] and a yield of 0.9 mol/mol. With its desirable characteristics, E. coli BT-10 is a promising strain for commercial 1,2,4-butanetriol production. [ABSTRACT FROM AUTHOR]

Corn cob is a major waste mass-produced in corn agriculture. Corn cob hydrolysate containing xylose, arabinose, and glucose is the hydrolysis product of corn cob. Herein, a recombinant Escherichia coli strain BT-10 was constructed to transform corn cob hydrolysate into 1,2,4-butanetriol, a platform substance with diversified applications. To eliminate catabolite repression and enhance NADPH supply for alcohol dehydrogenase YqhD catalyzed 1,2,4-butanetriol generation, ptsG encoding glucose transporter EIICBGlc and pgi encoding phosphoglucose isomerase were deleted. With four heterologous enzymes including xylose dehydrogenase, xylonolactonase, xylonate dehydratase, α-ketoacid decarboxylase and endogenous YqhD, E. coli BT-10 can produce 36.63 g/L 1,2,4-butanetriol with a productivity of 1.14 g/[L·h] using xylose as substrate. When corn cob hydrolysate was used as the substrate, 43.4 g/L 1,2,4-butanetriol was generated with a productivity of 1.09 g/[L·h] and a yield of 0.9 mol/mol. With its desirable characteristics, E. coli BT-10 is a promising strain for commercial 1,2,4-butanetriol production. [ABSTRACT FROM AUTHOR]

Background: Cost-effective production of biofuels from lignocellulose requires the fermentation of d-xylose. Many yeast species within and closely related to the genera Spathaspora and Scheffersomyces (both of the order Serinales) natively assimilate and ferment xylose. Other species consume xylose inefficiently, leading to extracellular accumulation of xylitol. Xylitol excretion is thought to be due to the different cofactor requirements of the first two steps of xylose metabolism. Xylose reductase (XR) generally uses NADPH to reduce xylose to xylitol, while xylitol dehydrogenase (XDH) generally uses NAD+ to oxidize xylitol to xylulose, creating an imbalanced redox pathway. This imbalance is thought to be particularly consequential in hypoxic or anoxic environments. Results: We screened the growth of xylose-fermenting yeast species in high and moderate aeration and identified both ethanol producers and xylitol producers. Selected species were further characterized for their XR and XDH cofactor preferences by enzyme assays and gene expression patterns by RNA-Seq. Our data revealed that xylose metabolism is more redox balanced in some species, but it is strongly affected by oxygen levels. Under high aeration, most species switched from ethanol production to xylitol accumulation, despite the availability of ample oxygen to accept electrons from NADH. This switch was followed by decreases in enzyme activity and the expression of genes related to xylose metabolism, suggesting that bottlenecks in xylose fermentation are not always due to cofactor preferences. Finally, we expressed XYL genes from multiple Scheffersomyces species in a strain of Saccharomyces cerevisiae. Recombinant S. cerevisiae expressing XYL1 from Scheffersomyces xylosifermentans, which encodes an XR without a cofactor preference, showed improved anaerobic growth on xylose as the primary carbon source compared to S. cerevisiae strain expressing XYL genes from Scheffersomyces stipitis. Conclusion: Collectively, our data do not support the hypothesis that xylitol accumulation occurs primarily due to differences in cofactor preferences between xylose reductase and xylitol dehydrogenase; instead, gene expression plays a major role in response to oxygen levels. We have also identified the yeast Sc. xylosifermentans as a potential source for genes that can be engineered into S. cerevisiae to improve xylose fermentation and biofuel production. [ABSTRACT FROM AUTHOR]

1,2,4-butanetriol (BT) is a polyol with unique chemical properties, which has a stereocenter and can be divided into D-BT (the S-enantiomer) and L-BT (the R-enantiomer). BT can be used for the synthesis of 1,2,4-butanetriol trinitrate, 3-hydroxytetrahydrofuran, polyurethane, and other chemicals. It is widely used in the military industry, medicine, tobacco, polymer. At present, the BT is mainly synthesized by chemical methods, which are accompanied by harsh reaction conditions, poor selectivity, many by-products, and environmental pollution. Therefore, BT biosynthesis methods with the advantages of mild reaction conditions and green sustainability have become a current research hotspot. In this paper, the research status of microbial synthesis of BT was summarized from the following three aspects: (1) the biosynthetic pathway establishment for BT from xylose; (2) metabolic engineering strategies employed for improving BT production from xylose; (3) other substrates for BT production. Finally, the challenges and prospects of biosynthetic BT were discussed for future methods to improve competitiveness for industrial production. [ABSTRACT FROM AUTHOR]

Corn straw is an abundant and renewable alternative for microbial biopolymer production. In this paper, an engineered Sphingomonas sanxanigenens NXG‐P916 capable of co‐utilising glucose and xylose from corn straw total hydrolysate to produce xanthan gum was constructed. This strain was obtained by introducing the xanthan gum synthetic operon gum as a module into the genome of the constructed chassis strain NXdPE that could mass produce activated precursors of polysaccharide, and in which the transcriptional levels of gum genes were optimised by screening for a more appropriate promoter, P916. As a result, strain NXG‐P916 produced 9.48 ± 0.34 g of xanthan gum per kg of fermentation broth (g/kg) when glucose was used as a carbon source, which was 2.1 times improved over the original engineering strain NXdPE::gum. Furthermore, in batch fermentation, 12.72 ± 0.75 g/kg xanthan gum was produced from the corn straw total hydrolysate containing both glucose and xylose, and the producing xanthan gum showed an ultrahigh molecular weight (UHMW) of 6.04 × 107 Da, which was increased by 15.8 times. Therefore, the great potential of producing UHMW xanthan gum by Sphingomonas sanxanigenens was proved, and the chassis NXdPE has the prospect of becoming an attractive platform organism producing polysaccharides derived from biomass hydrolysates. [ABSTRACT FROM AUTHOR]

As advances are made toward the industrial feasibility of mass-producing biofuels and commodity chemicals with sugar-fermenting microbes, high feedstock costs continue to inhibit commercial application. Hydrolyzed lignocellulosic biomass represents an ideal feedstock for these purposes as it is cheap and prevalent. However, many microbes, including Escherichia coli, struggle to efficiently utilize this mixture of hexose and pentose sugars due to the regulation of the carbon catabolite repression (CCR) system. CCR causes a sequential utilization of sugars, rather than simultaneous utilization, resulting in reduced carbon yield and complex process implications in fed-batch fermentation. A mutant of the gene encoding the cyclic AMP receptor protein, crp*, has been shown to disable CCR and improve the co-utilization of mixed sugar substrates. Here, we present the strain construction and characterization of a site-specific crp* chromosomal mutant in E. coli BL21 star (DE3). The crp* mutant strain demonstrates simultaneous consumption of glucose and xylose, suggesting a deregulated CCR system. The proteomics further showed that glucose was routed to the C5 carbon utilization pathways to support both de novo nucleotide synthesis and energy production in the crp* mutant strain. Metabolite analyses further show that overflow metabolism contributes to the slower growth in the crp* mutant. This highly characterized strain can be particularly beneficial for chemical production by simultaneously utilizing both C5 and C6 substrates from lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

BACKGROUND: Pistachio shell is a valuable lignocellulosic biomass because almost 90% of its hemicellulose fraction is xylan, which can be converted into high value‐added compounds such as xylooligosaccarides, xylose, xylitol and furfural. The present study represents a green and novel approach to produce xylose from lignocellulosic biomass. Microwave‐assisted high‐pressure CO2/H2O hydrolysis (MW‐HPCO2) comprising a combination never previously used was performed to produce xylose from pistachio shell. RESULTS: Response surface methodology with a Box–Behnken design was implemented to optimize microwave‐assisted high‐pressure CO2/H2O hydrolysis (MW‐HPCO2). The effect of temperature, time and liquid‐to‐solid ratio was studied in the ranges of 180–210 °C, 10–30 min and 5–30 mL g−1, respectively. A maximum xylose yield of 61.39% and minimum degradation compounds (5‐hydroxymethyl furfural and furfural) of 11.07% were attained under reaction conditions of 190 °C, 30 min and 18 mL g−1. CONCLUSION: The results showed that hydrolysis temperature, time and liquid‐to‐solid ratio had a strong influence on the xylose yield, as well as on the formation of degradation compounds. MW‐HPCO2 significantly increased accessibility to cellulose‐derived products in the subsequent enzymatic hydrolysis. The results of the present study reveal that MW‐HPCO2 can be a promising green technique for the hydrolysis of lignocellulosic biomass. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

During the normal production of ethanol from pretreated lignocellulosic biomass, only the solid fraction containing C6 sugars is generally used by unmodified yeasts in the fermentation process – the remaining liquid fraction, rich in xylose, is used almost exclusively by genetically modified organisms (GMOs) or for other purposes. As the liquor can be used in the manufacture of a series of chemical inputs, microorganisms that metabolize C5 sugars from different sources were initially isolated with the aim of converting these sugars into acetic acid (AA) and lactic acid (LA). Experiments were carried out with pretreated elephant grass liquor, evaluating the effect of adding commonly referenced nutrients through experimental design. Thus, the present work involves the isolation, screening, and molecular characterization of bacteria, easily found in nature, with the potential to metabolize xylose and produce AA and LA, with yields similar or superior to those shown in studies employing GMOs. Using wild‐type strains, high yields were obtained with Acetobacter cerevisiae (0.96 g LA and 0.71 g AA per g total sugars) and Levilactobacillus brevis (0.77 g LA and 0.61 g AA per g total sugars) in relation to the organic acids of interest, highlighting the total conversion of the sugar blend (xylose, glucose, and arabinose) in 24 h. Ammonium citrate also significantly influenced the final yields, being responsible for the increase in production. The results are useful for biorefinery platforms and may contribute to the full use of sugars released in the lignocellulosic pretreatment of raw materials. [ABSTRACT FROM AUTHOR]

Anthranilate and its derivatives are important basic chemicals for the synthesis of polyurethanes as well as various dyes and food additives. Today, anthranilate is mainly chemically produced from petroleum‐derived xylene, but this shikimate pathway intermediate could be also obtained biotechnologically. In this study, Corynebacterium glutamicum was engineered for the microbial production of anthranilate from a carbon source mixture of glucose and xylose. First, a feedback‐resistant 3‐deoxy‐arabinoheptulosonate‐7‐phosphate synthase from Escherichia coli, catalysing the first step of the shikimate pathway, was functionally introduced into C. glutamicum to enable anthranilate production. Modulation of the translation efficiency of the genes for the shikimate kinase (aroK) and the anthranilate phosphoribosyltransferase (trpD) improved product formation. Deletion of two genes, one for a putative phosphatase (nagD) and one for a quinate/shikimate dehydrogenase (qsuD), abolished by‐product formation of glycerol and quinate. However, the introduction of an engineered anthranilate synthase (TrpEG) unresponsive to feedback inhibition by tryptophan had the most pronounced effect on anthranilate production. Component I of this enzyme (TrpE) was engineered using a biosensor‐based in vivo screening strategy for identifying variants with increased feedback resistance in a semi‐rational library of TrpE muteins. The final strain accumulated up to 5.9 g/L (43 mM) anthranilate in a defined CGXII medium from a mixture of glucose and xylose in bioreactor cultivations. We believe that the constructed C. glutamicum variants are not only limited to anthranilate production but could also be suitable for the synthesis of other biotechnologically interesting shikimate pathway intermediates or any other aromatic compound derived thereof. [ABSTRACT FROM AUTHOR]

Areca nut husk is the most promising alternative source of low-cost raw materials because it contains a considerable amount of five-carbon monosaccharide sugar in the form of xylose. This polymeric sugar can be isolated and transformed into a value-added chemical using fermentation. To extract sugars from areca nut husk fibers, preliminary pretreatment, such as dilute acid hydrolysis (H2SO4), was performed. The hemicellulosic hydrolysate of areca nut husk can produce xylitol through fermentation, but toxic components inhibit the growth of microorganisms. To overcome this, a series of detoxification treatments, including pH adjustment, activated charcoal, and ion exchange resin, were carried out to reduce the concentration of inhibitors in the hydrolysate. This study reports a remarkable 99% removal of inhibitors in the hemicellulosic hydrolysate. Subsequently, a fermentation process using Candida tropicalis (MTCC6192) was executed with the detoxified hemicellulosic hydrolysate of areca nut husk, yielding an optimum xylitol yield of 0.66 g/g. This study concludes that detoxification techniques like pH adjustment, activated charcoal, and ion exchange resins are the most economical and effective methods for eliminating toxic compounds in hemicellulosic hydrolysates. Therefore, the medium derived after detoxification from areca nut hydrolysate may be considered to have significant potential for xylitol production. [ABSTRACT FROM AUTHOR]

Traditional Beijing roast duck often suffers from uneven color and high sugar content after roasting. Water-in-oil (W/O) nanoemulsion is a promising alternative to replace high concentration of sugar solution used in sugaring process according to similarity-intermiscibility theory. Herein, 3% of xylose was embedded in the aqueous phase of W/O emulsion to replace 15% maltose solution. W/O emulsions with different ratios of lecithin (LEC) and polyglycerol polyricinoleate (PGPR) were constructed by high-speed homogenization and high-pressure homogenization. Distribution and penetration extent of solutions and emulsions through the duck skin, as well as the color uniformity of Beijing roast duck were analyzed. Emulsions with LEC:PGPR ratios of 1:3 and 2:2 had better stability. Stable interfacial film and spatial structure were important factors influencing emulsion stabilization. The stable W/O emulsions could more uniformly distribute onto the surface of duck skin and longitudinally penetrate through the skin than solutions. • Stability mechanisms of W/O nanoemulsions emulsified by PGPR and LEC were explored. • Beijing roast duck with emulsion instead of solution had a better odour and taste. • Color uniformity of Beijing roast duck was significantly improved. • Distribution and penetration of emulsions on the surface of duck skin was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Identification of 116 Brazilian yeasts capable of fermenting xylose for ethanol. • First isolation of Sugiyamaella carassensis yeast from insect guts for biofuel. • Use of antimycin A to enhance ethanol production under aerobic conditions. • Discovery of four yeast strains with high efficiency in ethanol production. • Analysis of yeast metabolism in response to electron transport chain inhibition. [ABSTRACT FROM AUTHOR]

S-scheme heterojunctions have become an emerging type of effective photocatalysts to convert biomass. However, there are few reports on the synergistic S-type heterojunction and oxygen vacancy enhanced photocatalytic biomass conversion. Here, an AgInS 2 @CeO 2 -x S-scheme heterojunction photocatalyst with abundant oxygen vacancies was developed through a simple thermal and mild annealing process, allowing for the simultaneous production of xylonic acid and CO. Under visible light, the xylonic acid yield and CO evolution rate reached 60.0% and 3689.9 μmol g−1 h−1, respectively, through the decomposition of xylose. It was found that the S-scheme staggered band structure could improve sunlight utilization, increase the reduction power of photogenerated electrons, and enhance the separation and transfer of photogenerated charge carriers. Furthermore, oxygen vacancies on the surface of CeO 2 for AgInS 2 @CeO 2 -x heterojunction can suppress the recombination of generated electrons and holes. This study offers a promising approach for designing artificial photosynthetic systems to promote photocatalytic biomass conversion. [Display omitted] • The AgInS 2 @CeO 2 -x S-scheme heterojunctions with enhanced CeO 2 oxygen defects were designed. • The synergism between S-scheme heterojunctions and oxygen vacancies accelerated charge separation of AgInS 2 @CeO 2 -x. • The CO evolution and xylonic acid yield reached 3689.9 μmol g−1 h−1 and 60.0%. • The yields of xylonic acid and CO via AgInS 2 @CeO 2 -20 were 1.39 and 1.44 times greater than AgInS 2. [ABSTRACT FROM AUTHOR]

The proficient synthesis of xylose and xylooligosaccharides (XOS) from lignocellulosic biomass proved to be a formidable undertaking, particularly in the absence of preliminary hemicellulose isolation. In this study, the potential of benzoic acid (BZA), a non-toxic and edible acidic catalyst, was assessed for the pretreatment of poplar in order to produce xylose and xylooligosaccharides (XOS). At low temperatures (< 160°C) or low acid concentrations (< 2%), the main product obtained from the depolymerization of hemicellulose was XOS, and no significant depolymerization occurred on a large scale. The results showed that the highest extraction yield of hemicellulose was 93.1% with 2% BZA at 160°C for 0.75 h, hemicellulose was mainly converted into xylose and XOS, with xylose accounting for 27.1% and XOS accounting for 46.7%. Meanwhile, the results of the process simulation of industrial energy consumption indicated that the amount of water added was the main factor affecting energy consumption in industrialization, followed by temperature. This study presented a promising approach for the industrial-scale manufacturing of xylose and XOS from poplar as a primary resource. [Display omitted] • Low concentration acid treatment separated 93.1% of hemicellulose. • Excellent cellulose and lignin retention yields of 83.0% and 87.5%, respectively. • Process simulation predicted that water volume was the main factor in load. [ABSTRACT FROM AUTHOR]

This study adopted a mixed experimental research design to investigate the effects of alkali and alkali-catalyzed ethanol pretreatment of poplar wood under different NaOH loadings on the pretreatment liquid, pretreatment solids, and polysaccharide conversion, with a particular emphasis on the utility of the lignin for subsequent conversion. Specifically, NaOH catalyzed ethanol pretreatment at 10% NaOH loading resulted in the removal of more than 80% lignin with >80% carbohydrates remaining in the residual solids. Simultaneous saccharification fermentation of this pretreated residue resulted in 29.09 g/L (72.84%) and 14.86 g/L (69.26%) of ethanol and xylose, respectively, following a fermentation period of 72 h. Then, an integrated evaluation of the lignin characterization in raw and pretreated residues was carried out to emphasize their influence on ethanol and xylose yield by two-dimensional heteronuclear single quantum coherence (2D-HSQC) NMR and gel permeation chromatography (GPC) analysis. The results showed that most of the side-chain structures were oxidized and the aryl-ether bond was dissociated with the synergistic influence of NaOH and ethanol treatment, accompanied by low molecular weight lignin obtained in the solid fraction. Overall, NaOH catalyzed ethanol pretreatment offered a strategy for selective biomass fractionation into carbohydrates conversion and lignin valorization with a high yield. • NaOH-catalyzed ethanol pretreatment is effective to bioethanol and xylose production. • >80% lignin removal with more than 80% cellulose/hemicellulose recovery was obtained. • The linear correlation between lignin inhibition and sugars conversion was analyzed. • Lignin inhibition positively related to its Mw, S/G units and β-O-4 linkages. [ABSTRACT FROM AUTHOR]

Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC), often reoccur due to the formation of intracellular bacterial colonies (IBCs) and antibiotic resistance. Given the significance of YadC for UPEC infection in our previous study, we developed D-xylose-decorated ɛ-poly-L-lysine (εPL)-based carbon dots (D-xyl@εPLCDs) that can be traced, and employed multi-step approaches to elucidate the functional roles of D-xyl@εPLCDs in UPEC infection. Compared to undecorated particles, D-xyl@εPLCDs demonstrate YadC-dependent bacterial targeting and exhibit enhanced bactericidal activities both intracellularly and extracellularly. Moreover, pre-treatment of D-xyl@εPLCDs before infection blocked the subsequent adhesion and invasion of UPEC to bladder epithelial cells 5637. Increase of ROS production and innate immune responses were observed in bladder epithelial cells 5637 treated with D-xyl@εPLCDs. In addition, treatment of D-xyl@εPLCDs post-infection facilitated clearance of UPEC in the bladders of the UTI mouse model, and reduced ultimate number of neutrophils, macrophages and inflammatory responses raised by invaded bacteria. Collectively, we presented a comprehensive evaluating system to show that D-xyl@εPLCDs exhibits superior bactericidal effects against UPEC, making them a promising candidate for drug development in clinical UTI therapeutics. [Display omitted] • D-xyl@εPLCDs are taken up by infected cells, allowing them to target and eradicate invaded UPEC. • ROS production and immune responses within cells are induced by D-xyl@εPLCDs, which is detrimental to invaded UPEC. • The direct attachment of D-xyl@εPLCDs to UPEC facilitates its bactericidal effect outside of cells. • D-xyl@εPLCD attachment to YadC in UPEC inhibits subsequent adhesion of UPEC to epithelial cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Establishment of the first whole-genome CRISPRi library in Y. lipolytica. • Discovery of 14 novel gene targets for improving furfural and acetic tolerance. • Tolerance to the highest known acetic acid content (0.35%, v/v) in Y. lipolytica. • Tolerance mechanism entails enhanced cell division and decreased ROS level. • Tolerance to dual inhibitors during co-utilization of glucose and xylose. Abundant renewable resource lignocellulosic biomass possesses tremendous potential for green biomanufacturing, while its efficient utilization by Yarrowia lipolytica , an attractive biochemical production host, is restricted since the presence of inhibitors furfural and acetic acid in lignocellulosic hydrolysate. Given deficient understanding of inherent interactions between inhibitors and cellular metabolism, sufficiently mining relevant genes is necessary. Herein, 14 novel gene targets were discovered using clustered regularly interspaced short palindromic repeats interference library in Y. lipolytica , achieving tolerance to 0.35 % (v/v) acetic acid (the highest concentration reported in Y. lipolytica), 4.8 mM furfural, or a combination of 2.4 mM furfural and 0.15 % (v/v) acetic acid. The tolerance mechanism might involve improvement of cell division and decrease of reactive oxygen species level. Transcriptional repression of effective gene targets still enabled tolerance when xylose was a carbon source. This work forms a robust foundation for improving microbial tolerance to lignocellulose-derived inhibitors and revealing underlying mechanism. [ABSTRACT FROM AUTHOR]

• A kinetic framework was provided for biomass compounds released in subW. • Secondary char was formed by increasing T from sugar soluble degradation products. • Maillard reactions between sugars and amino acids in subW led to faster reaction loss. • Dehydration products formation was retarded in sugar + amino acid systems. • Higher relative reactivity in Maillard reactions was observed for xylose over glucose. A systematic kinetic study was conducted in subcritical water medium in the temperature range from 150 to 200 °C for pure glucose, xylose, proline and aspartic acid as well as binary mixtures of sugars + amino acids to understand the reaction kinetics and interactions among biomass components and to discern the influence of Maillard reaction (MR) on the overall reaction kinetics. The main degradation products identified for glucose and xylose were the respective dehydration products, hydroxymethyl furfural and furfural, yielding an increasing solid residue with temperature (15.9 wt% at 200 °C) with an augmented heating value. The degradation of sugars and amino acids in binary systems was faster compared to pure compounds due to MR and the production of dehydration products was delayed when considering total sugar conversion. Higher relative reactivity in MR was observed for xylose over glucose showing also higher antioxidant activity. [ABSTRACT FROM AUTHOR]

Hierarchical fluoride-containing zeolite HY (Hie-HY(F)) is an interesting material because it tunes both a high mesoporosity and a moderate acid property, which could benefit the transformation of xylose to xylitol. Herein, we synthesized a new Hie-HY(F) by etching NH 4 Y with ammonium fluoride (NH 4 F) under ultrasonication at 60 °C for 20, 40, and 60 min. After etching with NH 4 F solution, the Hie-HY(F)s contained fluoride in the zeolite frameworks with high mesoporosity and moderate acid properties. The sonication time longer than 20 min caused the structure to collapse rather than the creation of mesoporosity. The Hie-HY(F)s were further used as supports for the Ru catalyst. When loaded with Ru precursor and calcined in air, RuO 2 phase was formed in all catalysts. The RuO 2 supported on Hie-HY(F)s had a lower reduction temperature than that on HY. Ru supported on Hie-HY(F)-20 gave the reactivity of xylose conversion to xylitol, the highest yield of 80.1 %, providing the reusability up to four cycles. [Display omitted] • Synthesis of hierarchical fluoride-containing zeolite Y (Hie-HY(F)s) was disclosed. • Hie-HY(F)s was done by etching in NH 4 F solution under sonication at various times. • Dealumination and fluorination played a crucial role in mesoporosity and acidity. • Hie-HY(F)s was used as a novel support for Ru in xylose conversion to xylitol. • Ru/Hie-HY(F)-20 gave the highest xylitol productivity, 80.1 % yield. [ABSTRACT FROM AUTHOR]

• The optimal enzymes were selected for each reaction of the (S)-1,2,4-butanetriol artificial synthetic pathway. • A recombinant strain E. coli BL21(DE3) was constructed to co-expressing these four genes. • The cultivation of the recombinant E. coli strain and reaction conditions were optimized. • (S)-1,2,4-Butanetriol was synthesized in one-pot from 200 g/L d -xylose in 74% isolated yield and >99% ee using the E. coli whole cells. (S)-1,2,4-butanotriol is an important four carbon platform compound with extensive applications in many fields. Traditional chemical methods involving harsh reaction conditions and poor selectivity are environmentally unfriendly. Biosynthetic methods have made significant progress, but still cannot meet the needs of industrial production. In this study, a whole-cell biocatalytic system have been developed for the efficient production of (S)-1,2,4-butanotriol from d- xylose. d -xylose dehydrogenase (CcXylB), d -xylonate dehydratase (TaXylD), 2-keto acid decarboxylase (SaPDC) and aldehyde reductase (EqAdhP) with high activity were obtained by screening the libraries of these enzymes. The plasmid pRSFDuet-TaXylD-T7-CcXylB-SaPDC-T7-EqAdhP (P5) was constructed and introduced into E. coli BL21(DE3) to give the recombinant strain E. coli BL21(DE3)-P5, which could completely convert 200 g/L d -xylose to (S)-1,2,4-butanotriol in 74% isolated yield and >99% ee under the optimized cultivation and reaction conditions. This study provides a high-performance biocatalyst with potential industrial application for the synthesis of (S)-1,2,4-butanotriol from renewable resources. [Display omitted] [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass (LCB) has been a lucrative feedstock for developing biochemical products due to its rich organic content, low carbon footprint and abundant accessibility. The recalcitrant nature of this feedstock is a foremost bottleneck. It needs suitable pretreatment techniques to achieve a high yield of sugar fractions such as glucose and xylose with low inhibitory components. Cellulosic sugars are commonly used for the bio-manufacturing process, and the xylose sugar, which is predominant in the hemicellulosic fraction, is rejected as most cell factories lack the five‑carbon metabolic pathways. In the present review, more emphasis was placed on the efficient pretreatment techniques developed for disintegrating LCB and enhancing xylose sugars. Further, the transformation of the xylose to value-added products through chemo-catalytic routes was highlighted. In addition, the review also recapitulates the sustainable production of biochemicals by native xylose assimilating microbes and engineering the metabolic pathway to ameliorate biomanufacturing using xylose as the sole carbon source. Overall, this review will give an edge on the bioprocessing of microbial metabolism for the efficient utilization of xylose in the LCB. [ABSTRACT FROM AUTHOR]

Green high-surface area Ordered Mesoporous Carbons (OMCs) (576–948 m2/g) were successfully synthesized by the hard template method using xylose, glucose and lignin solutions obtained from almond shells, a local biomass waste, as carbon precursors, and SBA-15 as a template. The catalytic potential of OMCs, as catalytic supports or as catalysts, has been preliminarily tested for different reactions of interest. A dried sulfonic-acid treated OMC, obtained from xylose extract, led to full conversion and 92% selectivity to di- and tri-ethers of glycerol for the glycerol etherification with isobutene at 80 °C. A sulfonic-acid treated OMC, obtained from glucose, presented a higher turnover frequency (TOF) value and slightly lower selectivity to levulinic acid than commercial Amberlyst-15 for the conversion of 5-hydroxymethylfurfural at 180 °C. The use of an OMC obtained from lignin as catalytic support of a nickel catalyst combined with H-Beta led to 78% of selectivity to cyclohexane at total conversion for the hydrodeoxygenation of guaiacol at 180 °C. [Display omitted] • Ordered mesoporous carbons were prepared from xylose, glucose and lignin from biomass. • % of selectivity to h-GTBE was achieved with dried sulfonic-acid OMC from xylose. • Moderate selectivity to levulinic acid was obtained with sulfonic-acid OMC from glucose. • Ni supported on OMC from lignin combined with H-Beta led 78 % of cyclohexane selectivity. • Whole use of biomass waste is proposed to develop the circular bioeconomy concept. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple and efficient process for the synthesis of hydroxyl functionalized propiolate bio-monomers derived from D/L xylose and 2-deoxy-D-ribose, respectively. • Regio- and stereoregular poly(vinyl ether ester)s with high molecular weight (up to 20.4 kg mol−1) can be obtained at ambient temperature by hydroxyl-yne click polymerization, catalyzed by commercially available organic amines. • The incorporation of rigid structure and stereochemistry into the polymer chain simultaneously enhanced the thermal stability (T d,5% up to 340 °C) and glass transition temperatures (T g up to 143 °C). • These sugar-based click polymers can be selectively depolymerized employing 1-butanethiol in the presence of N -heterocyclic carbene as organocatalyst, yielding valuable monosaccharide derivatives in almost quantitative yields. The development of sustainable routes to degradable and bio-based polymers offers a promising solution to tackle the global plastic waste crisis. Herein, three hydroxyl functionalized propiolate bio-monomers have been selectively synthesized from D/L xylose and 2-deoxy-D-ribose, and polymerized via hydroxyl-yne click polymerization catalyzed by commercially available organic amines. The polymerization smoothly proceeded at room temperature to produce sequence-defined poly(vinyl ether ester)s with high thermal stability and high glass transition temperatures, due to the introduction of the rigid cyclic structure and specific stereo-configuration into the polymer backbone. More importantly, the resultant sugar-based poly(vinyl ether ester)s can be selectively depolymerized employing 1-butanethiol in the presence of N -heterocyclic carbene as organocatalyst, yielding thioacetal-functionalized monosaccharide derivatives in good to excellent yields. [ABSTRACT FROM AUTHOR]

Glycolipids are biodegradable nonionic sugar surfactants and can be produced from renewable resources, making these materials suitable for sustainable development. Herein, the thermal properties, liquid crystalline phases, and structures of Guerbet branched chain α -D-xylosides with variable chain lengths (C 8 to C 24 total carbons) have been investigated by differential scanning calorimetry, optical polarizing microscopy, and X-ray scattering, respectively. In the dry state, the α -D-xylosides were either in a crystalline or a gel phase-like state. In the presence of water, the two shorter chain members formed lamellar and sponge phases. At relatively higher temperatures and water concentrations, those with longer chains exhibited inverse curved phases of hexagonal and Fd 3 m micellar cubic. These α -D-xylosides were then used as an emulsifier to produce the n -alkane/water emulsions of oil-in-water type at room temperature. The n -dodecane/water emulsified using middle chain xyloside i.e., 2-hexyl-decyl-α-D-xyloside gave the most stable and highest formation of emulsion layer of more than 90 % of the total system volume. [Display omitted] • The anhydrous α -D-xylosides were either in a crystalline or a gel-like state. • The hydrated αXylC 6 C 2 and αXylC 8 C 4 naturally form lamellar and sponge phase, respectively. • The hydrated αXylC 10 C 6 exhibits hexagonal phase while αXylC 12 C 8 and αXylC 14 C 10 give Fd 3 m phase. • n -Dodecane/water emulsified using αXylC 10 C 6 gives the highest formation of emulsion layer. [ABSTRACT FROM AUTHOR]

[Display omitted] • A core–shell catalyst mZSM-5@SO 4 2-/mSiO 2 composed of mZSM-5 core and SO 4 2-/mSiO 2 shell was prepared by the soft template method. • The proximity and hierarchy of acidic sites within the core–shell catalyst were constructed to regulate the transport of key intermediates. • The acid ratio was adjusted by introducing the Brønsted acid sites directly into the shell while the core active sites remained unchanged. • The reaction path and mechanism of core–shell catalyst in the preparation of furfural from xylose were revealed. A core–shell catalyst mZSM-5@SO 4 2-/mSiO 2 composed of mZSM-5 core and SO 4 2-/mSiO 2 shell was prepared by the soft template method. Core-shell structure could promote the building of Brønsted -Lewis (B-L) acids interface and significantly improve the synergistic effect of B-L. In this paper, the Brønsted/Lewis (B/L) of mZSM-5@SO 4 2-/mSiO 2 was targeted regulating by innovatively introducing Brønsted acid (BA) sites into the shell. The optimal mZSM-5@SO 4 2-/mSiO 2 catalyst (B/L = 0.142) could achieve 72.1 % furfural yield at 140 ℃ for 1 h. In addition, 70.2 % furfural yield could be obtained after the catalyst was recycled and regenerated for 5 times. Combining In-situ IR and 13C NMR, the reaction path was revealed in detail: xylose was first isomerized to xylulose and then dehydrated to furfural. This paper provides a research idea for the directional regulation of dual active sites of cascade reaction catalysts. [ABSTRACT FROM AUTHOR]

Hydrothermal liquefication of biomass to produce high-quality chemicals and liquid fuels is considered as a renewable and sustainable technology. Herein, a one-step hydrothermal method was used to prepare microcrystalline cellulose supported carbon-based catalyst PTA-BC with the activation factor of phosphotungstic acid. It was demonstrated by Py-FTIR, NH 3 -TPD and XPS that PTA-BC is not only rich in functional groups but also contains Brønsted acid sites (hydroxyl groups) and Lewis acid sites (C C, carboxyl groups). After experimental optimization, the optimum yield of furfural obtained from xylose catalyzed by PTA-BC was 81.02% at the reaction temperature of 180 °C and the reaction time of 20 min. The results show that PTA-BC contains –COOH, –OH and C C as catalytic sites and that the synergistic effect of these functional groups. The nature of the reaction solvent, appropriate reaction temperature and residence time are the main reasons for the good catalytic performance. This work provides a promising way for the synthesis of solid acid catalyst, which has a wide application prospect for the production of furfural. [Display omitted] • Solid acid catalyst was prepared by one step hydrothermal method. • GVL/water solvent green system had an excellent yield of furfural. • The optimum reaction condition of xylose conversion to furfural was obtained. • The reaction mechanism of xylose to furfural was revealed. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass (LCB) has been a lucrative feedstock for developing biochemical products due to its rich organic content, low carbon footprint and abundant accessibility. The recalcitrant nature of this feedstock is a foremost bottleneck. It needs suitable pretreatment techniques to achieve a high yield of sugar fractions such as glucose and xylose with low inhibitory components. Cellulosic sugars are commonly used for the bio-manufacturing process, and the xylose sugar, which is predominant in the hemicellulosic fraction, is rejected as most cell factories lack the five‑carbon metabolic pathways. In the present review, more emphasis was placed on the efficient pretreatment techniques developed for disintegrating LCB and enhancing xylose sugars. Further, the transformation of the xylose to value-added products through chemo-catalytic routes was highlighted. In addition, the review also recapitulates the sustainable production of biochemicals by native xylose assimilating microbes and engineering the metabolic pathway to ameliorate biomanufacturing using xylose as the sole carbon source. Overall, this review will give an edge on the bioprocessing of microbial metabolism for the efficient utilization of xylose in the LCB. [ABSTRACT FROM AUTHOR]

[Display omitted] • An acid-tolerant yeast, I. orientalis , was engineered for organic acid production. • Engineered I. orientalis , SD108XL, can consume xylose and produce lactic acid. • Without pH regulation, SD108XL had difficulty in producing lactic acid. • A self-buffering strategy helps produce lactic acid by reducing pH regulation. This study presents a cost-effective strategy for producing organic acids from glucose and xylose using the acid-tolerant yeast, Issatchenkia orientalis. I. orientalis was engineered to produce lactic acid from xylose, and the resulting strain, SD108XL, successfully converted sorghum hydrolysates into lactic acid. In order to enable low-pH fermentation, a self-buffering strategy, where the lactic acid generated by the SD108XL strain during fermentation served as a buffer, was developed. As a result, the SD108 strain produced 67 g/L of lactic acid from 73 g/L of glucose and 40 g/L of xylose, simulating a sugar composition of sorghum biomass hydrolysates. Moreover, techno-economic analysis underscored the efficiency of the self-buffering strategy in streamlining the downstream process, thereby reducing production costs. These results demonstrate the potential of I. orientalis as a platform strain for the cost-effective production of organic acids from cellulosic hydrolysates. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeS 2 ore boosts biohydrogen production kinetics. • Enhanced electron transfer via redox-active EPS and flavins. • Optimized electron flux distribution for butyrate production. • Clostridium genes upregulated, accelerating H 2 generation. In this study, we investigated the advantages of utilizing natural FeS 2 ore in the context of dark fermentative hydrogen production within a fermentation system employing heat-treated anaerobic granular sludge with xylose as the carbon source. The results demonstrated a significant improvement in both hydrogen production and the maximum rate, with increases of 2.58 and 4.2 times, respectively. Moreover, the presence of FeS 2 ore led to a reduction in lag time by more than 2–3 h. The enhanced biohydrogen production performance was attributed to factors such as the intracellular NADH/NAD+ ratio, redox-active components of extracellular polymeric substances, secreted flavins, as well as the presence of hydrogenase and nitrogenase. Furthermore, the FeS 2 ore served as a direct electron donor and acceptor during biohydrogen production. This study shed light on the underlying mechanisms contributing to the improved performance of biohydrogen production from xylose during dark fermentation through the supplementation of natural FeS 2 ore. [ABSTRACT FROM AUTHOR]

[Display omitted] • The efficient D-lactic acid production from G. amansii hydrolysate was achieved. • P. acicilactici fermented the mixed sugars of galactose, glucose and xylose without CCR. • SSCF of the pretreated and biodetoxified G. amansii was conducted using P. acidilactici. • A record high of D-lactic acid (41.4 g/L) from macroalgae biomass was obtained. Macroalgae biomass has been considered as a promising renewable feedstock for lactic acid production owing to its lignin-free, high carbohydrate content and high productivity. Herein, the D-lactic acid production from red macroalgae Gelidium amansii by Pediococcus acidilactici was investigated. The fermentable sugars in G. amansii acid-prehydrolysate were mainly galactose and glucose with a small amounts of xylose. P. acidilactici could simultaneously ferment the mixed sugars of galactose, glucose and xylose into D-lactic acid at high yield (0.90 g/g), without carbon catabolite repression (CCR). The assimilating pathways of these sugars in P. acidilactici were proposed based on the whole genome sequences. Simultaneous saccharification and co-fermentation (SSCF) of the pretreated and biodetoxified G. amansii was also conducted , a record high of D-lactic acid (41.4 g/L) from macroalgae biomass with the yield of 0.34 g/g dry feedstock was achieved. This study provided an important biorefinery strain for D-lactic acid production from macroalgae biomass. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient acetate production from photo-reduction of HCO 3 − and xylose reforming. • HCO 3 − and xylose are converted into •CO 2 − radicals forC— C coupling into acetate. • H-radicals in aqueous systems facilitate HCO 3 − conversion to produce C 2+. • Photo-reduction to produce acetate reaches 20% efficiency under 420-nm irradiation. • Elucidated pathways for solar-driven conversion of CO 2 and biomass into chemicals. Using CO 2 (or aqueous-CO 2 , HCO 3 −) and biomass as feedstock to produce chemicals under solar irradiation represents a promising approach to achieving the net-zero emission goal. In this study, we employed a highly efficient •H-forming photocatalyst to convert HCO 3 −, demonstrating the occurrence of C C coupling to produce C 2 -species. Under simulated solar illumination, the photocatalytic system consistently reduces HCO 3 − into acetate through the coupling of •CO 2 − radicals. Additionally, in the photoreforming of xylose, acetate emerges as the predominant product, likely resulting from the coupling of •CO 2 − derived from the interaction of formate and •OH. Notably, a C 6 -compound is generated through C C coupling of radicals originating from HCO 3 − and xylose. Achieving an overall apparent quantum efficiency of 26% under 420-nm irradiation, our work underscores the feasibility of concurrently photocatalyzing the conversion of CO 2 and biomass into chemicals through C C coupling. This study not only highlights the significance of our approach in contributing to the net-zero emission goal but also emphasizes the novelty of achieving concurrent photocatalytic conversion. [ABSTRACT FROM AUTHOR]

The inhibition of cross-linked lysinoalanine (LAL) formation in silkworm pupa protein isolates (SPPI) by Maillard reaction (using varying xylose concentration) and ultrasound treatment was studied. Results showed that sonicated SPPI was effectively grafted with high concentration of xylose (5 %), resulting in the lowest LAL content, which was 48.75 % and 30.64 % lower than the control and ultrasound-treated samples, respectively. Chemical bond analysis showed that the combined treatment destroyed the ionic bonds, intrachain (g-g-t), and interchain (g-g-g) disulfide bonds, but stimulated the polymerization of hydrogen and hydrophobic bonds between SPPI and xylose, and as well enhanced the net negative charge between SPPI/Xylose complexes. The particles of the complexes were more loose, dispersed and rough, and had a stronger hydrophilic microenvironment, accompanied by alterations in microscopic, secondary and tertiary structures. Ultrasound treatment induced the breakdown of the oxidative cross-linking in SPPI, and promoted the sulfhydryl group-dehydroalanine binding and the carbonyl-amino condensation of the protein and xylose, and thus inhibited the formation of cross-linked LAL. Furthermore, the physicochemical and structural parameters were highly interrelated with cross-linked LAL content (| r | > 0.9). The outcomes provided a novel avenue and theoretical basis for minimizing LAL formation in SPPI and improving the nutrition and safety of SPPI. [Display omitted] • The synergy of 5 % xylose and ultrasound treatment on LAL inhibition was prominent. • Ultrasound promoted the nondisulphide crosslinks between SPPI and xylose. • Ultrasound-induced enhancement of carbonyl-amino condensation reduced LAL linkage. • The structures and oxidative linkages of SPPI were altered by combined treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cascade fractionation strategy for deconstructing bamboo shoot shells was proposed. • The xylose yield under optimal conditions (160 °C, 2 %, 1 h) reached 90.73 %. • High delignification ratio (90.25%) and glucose yield (93.35%) were achieved. • Lignin nanoparticles (∼31.51 nm) were prepared by simple sonication. • Multiple enrichment cycle strategy promoted demethoxylation of lignin. The high complexity and compactness of inherent structure in lignocellulosic materials (LCM) leads to the difficulty of fractionation and conversion of its major component, which is the key obstacle limiting the value-added utilization of LCM. In this work, a cascade fractionation strategy, coupling catalytic hydrothermal pretreatment (CHTP, choline chloride: ethylene glycol: AlCl 3 , ChCl/ EG/ AlCl 3) with hydrated alkaline deep eutectic solvent (HADES, triethylbenzyl ammonium chloride/ethanolamine, TEBAC/EM) treatment, was proposed to fractionate dendrocalamus latiftorus munro shoot shells (DLMSS). The results showed that considerably high hemicelluloses removal (94.57 %) and xylose yield (90.73 %) were achieved by the first step (CHTP, 160 °C, 1 h, 2 % of catalyst loading). The cascaded HADES treatment realized 90.25 % delignification ratio under the optimal conditions (120 °C, 3 h, 75 % of ADES loading), and the obtained residue could be easily converted into high-yield (93.35 %) of glucose via enzymatic saccharification. In addition, multiple enrichment cycle strategy (MECS) was performed to facilitate the recyclability of the HADES. The results showed that the enriched lignin recovered by MECS was activated by in-situ demethoxylation reaction. And such lignin fraction could be easily assembled into homogeneous lignin nanoparticles (LNPs, ∼31.51 nm in diameter) by simple sonication. Meanwhile, the MECS signally energized the antioxidant activity of the enriched lignin. Based on the high-efficiency cascade fractionation with the coupled CHTP-HADES fractionation strategy, it will observably boost the effectiveness and scalability of the advanced biorefinery strategy. [ABSTRACT FROM AUTHOR]

Commercially available cellulase cocktails frequently demonstrate high efficiency in hydrolyzing easily digestible pretreated biomass, which often lacks hemicellulose and/or lignin fractions. However, the challenge arises with enzymatic hydrolysis of mildly pretreated lignocellulosic biomasses, which contain cellulose, hemicellulose and lignin in high proportions. This study aimed to address this question by evaluating the supplementation of a commercial cellulolytic cocktail with accessory hemicellulases and two additives (H 2 O 2 and Tween® 80). Statistical optimization methods were employed to enhance the release of glucose and xylose from mildly pretreated sugarcane bagasse. The optimized supplement composition resulted in the production of 304 and 124 mg g−1 DM of glucose and xylose, respectively, significantly increasing glucose release by 84% and xylose release by 94% compared to using only the cellulolytic cocktail. This enhancement might be attributed to a coordinated hemicellulases action degrading hemicellulose, creating more space for cellulase activity, potentially boosted by the presence of H 2 O 2 and Tween® 80. However, the addition of different concentrations of H 2 O 2 in combination with hemicellulase and Tween® 80 did not result a significant difference on sugar release, which could be attributed to the limited range of concentrations studied (5 to 65 µM). The results obtained in this study using the mix of three supplements were also compared to the addition of only hemicellulase and only Tween® 80 to the cellulolytic cocktail. A significant increase in glucose release of 39% and 41%, respectively, was observed when using the optimized combination. For xylose, the increase was 38% and 41%, respectively. This study underscores the substantial potential in optimizing enzyme cocktails for the hydrolysis of mildly pretreated lignocellulosic biomass by using enzymes and additive combinations tailored to the specific biomass composition. [Display omitted] • Enzyme cocktail composition was optimized using a Box-Benhken design. • Addition of hemicellulase and Tween® 80 led to higher glucose and xylose production. • Addition of H2O2 (5-65 μM) did not result a significant difference on sugar release. • Optimum condition increased glucose and xylose production in 84% and 94% respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1. Microwave intermittent heating can effectively regulate the Maillard reaction process. • 2. The rapid preparation of the Amadori compound (ARP) was realized by microwave heating. • 3. Dehydration rate and microwave effects were key factors to improve the yield of ARP. • 4. ARP can degrade rapidly and accelerate the Maillard reaction in microwave processing. • 5. ARP was expected to be an important color enhancer for microwave fast processed food. Directional and rapid formation of the Amadori rearrangement product (ARP) from the glutamic acid and xylose was achieved through intermittent microwave heating. The yield of ARP reached 58.09 % by subjecting the system to intermittent microwave heating at a power density of 10 W/g for 14 min. Dehydration rate and microwave effects were found to be key factors to optimize the conditions for directional and rapid preparation of the ARP. Through a comprehensive analysis of the ARP degradation and further browning under both conductive and microwave thermal processing, it was observed that microwave processing significantly accelerated the browning degree of systems, leading to a tenfold reduction in the heating time required for browning. This research presented a promising avenue for the development of novel and expedited methods for the production of ARP and highlighted the potential of ARP in enhancing color quality in fast-cooking applications utilizing microwave. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heterostructure of Mo-doped Co(CO 3) 0.5 OH on NiCo 2 S 4 is successfully constructed. • The dual electronic regulation effect greatly enhances the XOR activity. • NiCoS@CoMo/CC presents low overpotential and high cycle stability for XOR. • The yield and selectivity of xylose oxidation products show excellent. • The coupling effect of HER/XOR improved the generation rate of hydrogen fuel. The development of an advanced electrocatalyst is crucial to achieve low-cost and efficient biomass electrooxidation for assisting its practical application. In this study, we design a unique heterostructure of Mo-doped Co(CO 3) 0.5 OH coating on NiCo 2 S 4 nanowires for efficient xylose oxidation reaction (XOR). The as-prepared electrocatalyst requires only 1.28 V for XOR to achieve current density of 50 mA cm−2, and the electrocatalytic system exhibits the high formic acid (FA) yield of 63.22 % and excellent selectivity of 96.52 %, which still maintains unchanged after seven cycles. Furthermore, the two-electrode system by coupling XOR and hydrogen evolution reaction (HER) shows that product selectivity remained at least 96 %, while the hydrogen production rate higher than the original. This remarkable performance is attributed to the synergic effect of heterostructure and multi-component as confirmed by XPS and XRD analysis. This work puts forward an attractive approach for designing high electrocatalytic activity and selectivity electrocatalyst for biomass electrooxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Brewers' spent grain (BSG) was valorized for enzymes and lactic acid production. • Trichoderma sp. could effectively produce cellulase and β-glucosidase from BSG. • Successive solid-state and submerged fermentation most promoted enzyme production. • Fungal enzyme cocktail could be used for low-cost lactic acid production from BSG. • This approach may also be applicable to other similar agro-industrial wastes. This study aimed to increase the value of brewers' spent grain (BSG) by using it as feedstock to produce lignocellulolytic enzymes and lactic acid (LA). Twenty-two fungal strains were screened for lignocellulolytic enzyme production from BSG. Among them, Trichoderma sp. showed the highest cellulase activity (35.84 ± 0.27 U/g-BSG) and considerably high activities of xylanase (599.61 ± 23.09 U/g-BSG) and β-glucosidase (16.97 ± 0.77 U/g-BSG) under successive solid-state and submerged fermentation. The processes were successfully scaled up in a bioreactor. The enzyme cocktail was recovered and characterized. The maximum cellulase and xylanase activities were found at pH 5.0 and 50 °C, and the activities were highly stable at pH 4–8 and 30–50 °C. The enzyme cocktail was applied in simultaneous saccharification and fermentation of acid-pretreated BSG for LA production. The maximum LA obtained was 59.3 ± 1.0 g/L. This study has shown the efficient biovalorization of BSG, and this approach may also be applicable to other agro-industrial wastes. [ABSTRACT FROM AUTHOR]

Efficiently dissolving and separating cellulose from xylose residue is beneficial to realize the high added-value of lignocellulosic waste. In this work, theoretical prediction by using COSMO-RS and practical experiments were combined to investigate the extraction selectivity of ionic liquids (ILs) for cellulose and lignin. Two imidazolium-based ILs, 1-ethyl-3-methylimidazolium diethylphosphate ([Emim]DEP) and 1-allyl-3-methylimidazolium chloride ([Amim]Cl), were screened out from 425 ILs. These ILs were subsequently mixed with dimethyl sulfoxide (DMSO) to dissolve and separate cellulose from xylose residue. The cellulose extraction efficiency of [Emim]DEP/DMSO were optimized by regulating the content of xylose residue, dissolution temperature and time. As the cellulose content was 1.2 wt%, the dissolution temperature of 80 °C, and the dissolving time of 120 min, the cellulose extraction rate of xylose residue could reach as high as 99.3% in [Emim]DEP/DMSO, which is higher than that in [Amim]Cl/DMSO (95.4%). The higher cellulose and lower lignin dissolution capacities of [Emim]DEP indicated that [Emim]DEP was a promising solvent to realize the conversion and utilization of cellulose in agro-industrial residues. In addition, [Emim]DEP presents constant dissolution capacity even it was recycled for five times. Furthermore, the produced xylose residue cellulose film (XRCF) displayed a homogeneous and smooth morphology with a tensile strength of 55.9 MPa, which had great potential in packaging. • The theoretical extraction selectivity of ionic liquids for cellulose and lignin was investigated using COSMO-RS. • [Emim]DEP/DMSO system was screened out to efficiently separate cellulose from xylose residue by experimental conformation. • The cellulose extraction rate of xylose residue can reach as high as 99.3% in [Emim]DEP/DMSO system. • The prepared xylose residue cellulose film exhibited a homogeneous morphology with a tensile strength of 55.9 MPa. [ABSTRACT FROM AUTHOR]

• Acetate metabolic pathway via glyoxylate shunt in K. marxianus was revealed. • Enhanced glyoxylate shunt increased acetate metabolism to 122.7 % at 40 °C. • Overexpressing GPD2 and FDH1 further increased acetate uptake by 3.9 folds. • Toxic compounds detoxification enhanced lignocellulosic biomass conversion. • Foresight for the acetate utilization as an intermediate for reducing CO 2. Lignocellulosic biomass is a typical agriculture waste and a potential feedstock for the green biomanufacturing. However, insufficient utilization of carbon sources caused by inhibitors, especially acetic acid, hinders the economic bioconversion. Here, we demonstrated the acetate metabolic pathway via glyoxylate shunt in nonconventional yeast Kluyveromyces marxianus. Acetate metabolism increased to 122.7 % at 40 °C after overexpressing ICL1 and MLS1 , key genes of glyoxylate shunt revealed by transcriptomic data. Strengthening GPD2 and FDH1 further enhanced the robustness of the K. marxianus , acetate metabolism was significantly increased. Finally, the modified K. marxianus 1727–5-ICL1-MLS1-GPD2-FDH1 boosted the efficiency for xylose uptake up to 1.3 folds in non-detoxified lignocellulosic hydrolysate, benefiting from a 3.9-fold increase in acetate consumption. Our results propose a novel strategy for xylose assimilation by coupling acetate metabolism, contributing the bioconversion of sustainable lignocellulosic biomass. It also provides a new scheme for the total carbon utilization of lignocellulosic biomass, including carbon dioxide (CO 2) released from the biofuel production to achieve a circular economy. [ABSTRACT FROM AUTHOR]