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Areca nut husk (ANH) holds promise as a viable biomass source for xylose production. Xylose is a precursor for various biochemicals. However, the recalcitrant nature of ANH makes saccharification more complex. To address this, lime and acid pretreatments were carried out to enhance the susceptibility of biomass to saccharification. Before this, a compositional analysis was conducted to determine the initial constituents of the feedstock. Saccharification was conducted under the following conditions: 2% (wV−1) substrate loading, 100 rpm agitation, and 30 °C hydrolysis temperature for 12 h hydrolysis time at pH 4.5 to 5.0. However, parameters like xylanase enzyme loading were varied to enhance the saccharification of the ANH. The results demonstrated that acid‐treated husk (ATH), lime‐treated husk (LTH), and raw husk (RH) achieved the highest yield (gg−1) of reducing sugar, approximately 90, 83, and 15%, respectively, at an enzyme loading of 15.0 IUg−1. Various analytical techniques, including Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), zeta potential, thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) were used to examine structural changes in the native, pretreated, and saccharified residues of ANH. The analysis revealed that a significant amount of partial crystalline and amorphous cellulose in the ANH biomass was hydrolyzed during the saccharification process. However, saccharification also led to the removal of amorphous substances, disruption of the crystalline structure, and conversion of crystalline regions into amorphous domains. [ABSTRACT FROM AUTHOR]

Glycerol is a simple and important polyol in both biological and industrial field. To produce glycerol in an eco‐friendly manner, we established a one‐pot cascade reaction by fructose‐6‐phosphate aldolase (FSA) and aldehyde reductase (ALR) from formaldehyde (FALD) and its dimerized form glycolaldehyde (GALD) via L‐glyceraldehyde. For this, we characterized two FSAs at various conditions. Among them, FSA from Gilliamella apicola (GaFSA) has shown the higher L‐glyceraldehyde production activity in the phosphate buffer than the well‐known FSA from Escherichia coli (EcFSA) by more than 2 times. We also characterized two ALRs (xylose reductase from Candida tenuis; CtXR, the annotated DL‐glyceraldehyde reductase from Hypocrea jecorina; HjGLD) that specifically reduce L‐glyceraldehyde into glycerol. Bioproduction of glycerol from FALD and GALD was performed using GaFSA and CtXR, which produced ~8.8 mM glycerol from 25 mM of FALD and GALD (conversion yield of ~35 %). This suggested that a simple process would help in designing a green production of glycerol from a wasteful one‐carbon chemicals. [ABSTRACT FROM AUTHOR]

Microbial production of polyhydroxyalkanoate (PHA) is greatly restricted by high production cost arising from high‐temperature sterilization and expensive carbon sources. In this study, a low‐cost PHA production platform was established from Halomonas cupida J9. First, a marker‐less genome‐editing system was developed in H. cupida J9. Subsequently, H. cupida J9 was engineered to efficiently utilize xylose for PHA biosynthesis by introducing a new xylose metabolism module and blocking xylonate production. The engineered strain J9UΔxylD‐P8xylA has the highest PHA yield (2.81 g/L) obtained by Halomonas with xylose as the sole carbon source so far. This is the first report on the production of short‐ and medium‐chain‐length (SCL‐co‐MCL) PHA from xylose by Halomonas. Interestingly, J9UΔxylD‐P8xylA was capable of efficiently utilizing glucose and xylose as co‐carbon sources for PHA production. Furthermore, fed‐batch fermentation of J9UΔxylD‐P8xylA coupled to a glucose/xylose co‐feeding strategy reached up to 12.57 g/L PHA in a 5‐L bioreactor under open and unsterile condition. Utilization of corn straw hydrolysate as the carbon source by J9UΔxylD‐P8xylA reached 7.0 g/L cell dry weight (CDW) and 2.45 g/L PHA in an open fermentation. In summary, unsterile production in combination with inexpensive feedstock highlights the potential of the engineered strain for the low‐cost production of PHA from lignocellulose‐rich agriculture waste. [ABSTRACT FROM AUTHOR]

Four yeast isolates were obtained from rotting wood and galleries of passalid beetles collected in different sites of the Brazilian Amazonian Rainforest in Brazil. This yeast produces unconjugated allantoid asci each with a single elongated ascospore with curved ends. Sequence analysis of the internal transcribed spacer‐5.8 S region and the D1/D2 domains of the large subunit ribosomal RNA (rRNA) gene showed that the isolates represent a novel species of the genus Spathaspora. The novel species is phylogenetically related to a subclade containing Spathaspora arborariae and Spathaspora suhii. Phylogenomic analysis based on 1884 single‐copy orthologs for a set of Spathaspora species whose whole genome sequences are available confirmed that the novel species represented by strain UFMG‐CM‐Y285 is phylogenetically close to Sp. arborariae. The name Spathaspora marinasilvae sp. nov. is proposed to accommodate the novel species. The holotype of Sp. marinasilvae is CBS 13467 T (MycoBank 852799). The novel species was able to accumulate xylitol and produce ethanol from d‐xylose, a trait of biotechnological interest common to several species of the genus Spathaspora. Take‐away: The novel species Spathaspora marinasilvae was isolated, identified, and formally described.The genome sequence of Spathaspora marinasilvae is reported.Spathaspora marinasilvae assimilated and fermented d‐xylose with ethanol production and accumulation of xylitol. [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]

Almond hulls can be used as an inexpensive source of nutrients for producing fungi that can be used as nontraditional foods such as alternative protein, probiotics, and food ingredients. Nutrients were extracted from almond hulls using hot water and their utility in cultivating filamentous fungus Aspergillus awamori (A. awamori) in submerged cultivation was investigated using batch fermentation in flasks with passive aeration. The almond hulls extract supplied all the nutrients required for A. awamori growth. The uptake preference of various sugars was investigated and the growth kinetic parameters of A. awamori were determined. Utilization of sugars by A. awamori grown in almond hull extract proceeded sequentially with preference for glucose followed by sucrose, fructose, and then xylose. Compared to potato dextrose broth medium, the fungal biomass produced using almond hull extract as growth medium had higher protein (19.59%) and lower fat (1.50%) contents. The modified Gompertz model described the kinetics of A. awamori well with a lag phase of 0.18 days and a specific growth rate of 1.77 d−1. [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]

Effective separation of various components in biomass is critical for biorefinery. Autohydrolysis is a commercialized unit operation to remove hemicelluloses, such as xylan, in producing high‐quality cellulose (the so‐called dissolving pulp) in the pre‐hydrolysis kraft process. In the present study, the autohydrolysis of eucalyptus woodchips was investigated for the purpose of producing dissolving pulps, with a focus on the production of cellulose acetate grade dissolving pulp. First, the effects of liquid‐to‐solid ratio, maximum temperature, and time on hemicelluloses removal were comprehensively studied, and the total xylose saccharides concentration and total xylose saccharides yield were determined as a function of the P factor and log(Ro). The three‐variable Box–Behnken design of the response surface methodology was followed to optimize the autohydrolysis conditions, aiming to achieving the maximum removal of xylan. The as‐obtained optimal conditions were: liquid‐to‐solid ratio of 5.5 mL · g−1, maximum temperature of 165°C, and time of 120 min, with its P factor of 867 h and log(Ro) of 4.03. Under these conditions, the total xylose saccharides concentration was 16.43 g · L−1. Furthermore, the autohydrolysis yield was investigated. The results showed that the purity of as‐prepared cellulose substrate as a result of autohydrolysis at a P factor of 867 h (log(Ro) of 4.03) can meet the stringent requirement of cellulose acetate grade dissolving pulp. Furthermore, the pre‐hydrolysis liquor compositions were compared between the typical autohydrolysis conditions for rayon grade dissolving pulp (a P factor of 690 h and log(Ro) of 3.91) and the optimal conditions (a P factor of 867 h and log(Ro) of 4.03). [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]

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]

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]

Herein, the six‐membered sulfur‐containing cyclic carbonates was successfully synthesized from d‐ and l‐xylose through an environmental friendly process by employing carbonyl sulfide (COS) as a sustainable C1‐carbonation agent. The ring‐opening polymerization of the monomers were rapidly initiated by bifunctional organocatalysts and alkali metal alkoxides, respectively, under ambient reaction conditions. The resultant sulfur‐containing polycarbonates exhibit high‐temperature resistance and good optical properties. This work furnishes an original and practical strategy for utilizing COS as a sulfur feedstock in biopolymer synthesis. [ABSTRACT FROM AUTHOR]

The synthesis of sugar fatty acid esters (SFAEs) from lignocellulosic biomass and oleic acid (C18:1) was catalyzed by immobilized‐stabilized derivatives of Candida antarctica lipase B in a methyl ethyl ketone medium. After steam‐explosion pretreatment of mixed hardwoods and enzymatic hydrolysis at 15%wt solids, xylose and glucose were purified/concentrated to a mass ratio of ~3 to 1. These lignocellulosic sugars were superior to commercial sugars as the carbohydrate source for the esterification reaction in terms of sugar conversions. The highest conversions were obtained using 1.5% w/v of Novozyme 435 (N435, uncoated) as the biocatalyst for the synthesis of SFAEs. Coating the N435 with polyethyleneimine (PEI) prevented enzyme leakage into the reaction medium and produced 35% and 50% higher xylose and glucose conversions to SFAEs, respectively, at the same enzyme loading. After six 24 h reuse cycles with the PEI‐coated N435, xylose conversion decreased by 44%, while a 65% reduction in xylose conversion was observed with the uncoated lipase. Mass spectrometry analysis confirmed the production of xylose and glucose mono‐ and di‐esters. Our purified product presented an emulsion capacity (EC) close to that of a commercial sugar ester and the ECs of the xylose oleate, laurate, and palmitate synthesized in previous studies. © 2023 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Domestication is an excellent case study for understanding adaptation and multiple fungal lineages have been domesticated for fermenting food products. Studying domestication in fungi has thus both fundamental and applied interest. Genomic studies have revealed the existence of four populations within the blue‐cheese‐making fungus Penicillium roqueforti. The two cheese populations show footprints of domestication, but the adaptation of the two non‐cheese populations to their ecological niches (i.e., silage/spoiled food and lumber/spoiled food) has not been investigated yet. Here, we reveal the existence of a new P. roqueforti population, specific to French Termignon cheeses, produced using small‐scale traditional practices, with spontaneous blue mould colonisation. This Termignon population is genetically differentiated from the four previously identified populations, providing a novel source of genetic diversity for cheese making. The Termignon population indeed displayed substantial genetic diversity, both mating types, horizontally transferred regions previously detected in the non‐Roquefort population, and intermediate phenotypes between cheese and non‐cheese populations. Phenotypically, the non‐Roquefort cheese population was the most differentiated, with specific traits beneficial for cheese making, in particular higher tolerance to salt, to acidic pH and to lactic acid. Our results support the view that this clonal population, used for many cheese types in multiple countries, is a domesticated lineage on which humans exerted strong selection. The lumber/spoiled food and silage/spoiled food populations were not more tolerant to crop fungicides but showed faster growth in various carbon sources (e.g., dextrose, pectin, sucrose, xylose and/or lactose), which can be beneficial in their ecological niches. Such contrasted phenotypes between P. roqueforti populations, with beneficial traits for cheese‐making in the cheese populations and enhanced ability to metabolise sugars in the lumber/spoiled food population, support the inference of domestication in cheese fungi and more generally of adaptation to anthropized environments. [ABSTRACT FROM AUTHOR]

Hemicelluloses are a major component of lignocellulosic biomass. Different sugars can be obtained from hemicelluloses: xylose, arabinose, galactose, mannose, glucose. Their catalytic hydrogenation produces polyols: xylitol, arabinitol, dulcitol, mannitol, sorbitol, which are valuable chemicals and platform molecules. In this paper, the hydrogenation of sugars was investigated with a Ru/TiO2 catalyst. The influence of temperature, pressure, xylose concentration and catalyst amount was studied for xylose hydrogenation and a Langmuir‐Hinshelwood kinetic model was designed. The comparative study of five hemicellulose sugars showed a strong impact of sugar structure on hydrogenation rate: hexoses (glucose, mannose, galactose) react slower than pentoses (xylose, arabinose). [ABSTRACT FROM AUTHOR]

Xylanolytic enzymes, with both endo‐xylanase and arabinoxylan arabinofuranohydrolase (AXH) activities, are attractive for the economically feasible conversion of recalcitrant arabinoxylan. However, their characterization and utilization of these enzymes in biotechnological applications have been limited. Here, we characterize a novel bifunctional enzyme, rAbf43A, cloned from a bacterial consortium that exhibits AXH and endo‐xylanase activities. Hydrolytic pattern analyses revealed that the AXH activity belongs to AXHd3 because it attacked only the C(O)‐3‐linked arabinofuranosyl residues of double‐substituted xylopyranosyl units of arabinoxylan and arabinoxylan‐derived oligosaccharides, which are usually resistant to hydrolysis. The enzyme rAbf43A also liberated a series of xylo‐oligosaccharides (XOSs) from beechwood xylan, xylohexaose and xylopentaose, indicating that rAbf43A exhibited endo‐xylanase activity. Homology modelling based on AlphaFold2 and site‐directed mutagenesis identified three non‐catalytic residues (H161, A270 and L505) located in the substrate‐binding pocket essential for its dual‐functionality, while the mutation of A117 located in the −1 subsite to the proline residue only affected its endo‐xylanase activity. Additionally, rAbf43A showed significant synergistic action with the bifunctional xylanase/feruloyl esterase rXyn10A/Fae1A from the same bacterial consortium on insoluble wheat arabinoxylan and de‐starched wheat bran degradation. When rXyn10A/Fae1A was added to the rAbf43A pre‐hydrolyzed reactions, the amount of released reducing sugars, xylose and ferulic acid increased by 9.43% and 25.16%, 189.37% and 93.54%, 31.39% and 32.30%, respectively, in comparison with the sum of hydrolysis products released by each enzyme alone. The unique characteristics of rAbf43A position it as a promising candidate not only for designing high‐performance enzyme cocktails but also for investigating the structure–function relationship of GH43 multifunctional enzymes. [ABSTRACT FROM AUTHOR]

Cellulose and lignin nanoparticles are high‐value‐added products obtained from lignocellulosic biomasses through several steps of cellulose purification and lignin extraction. These steps drastically reduce the potential feedstock revenue when carried out as stand‐alone methodologies. To increase biomass yields, we describe here a strategy to design a biorefinery focused on producing cellulose and lignin nanoparticles as main products, but also aim to recover and benefit from other biomass components using only water‐based processes. Sequential pressurized liquid extractions and diluted acid and alkaline treatments were carried out to fractionate elephant grass biomass, yielding (for every 100 g of biomass): 30 g of cellulose pulp (converted to 9 g of cellulose nanocrystals and 9 g of cellulose nanofibers); 10 g of lignin (used to produce 8.5 g of stable colloidal lignin nanoparticles by probe‐sonication in water); 7.5 g of extractives (e.g. sterols and phenolics) and 23 g of xylose (converted to 4.1 g of furfural). Alternatively, to allow for the flexible use of the cellulose fraction in the proposed biorefinery, 22 g of glucose could be produced by enzymatic hydrolysis. The results demonstrate that water‐based processes are suitable for a holistic use of biomass, providing a comprehensive set of high‐value‐added co‐products that are renewable and cost‐effective chemical, cosmetic, food, polymer and pharmaceutical solutions. [ABSTRACT FROM AUTHOR]

Microbial consortia have great potential for the production of polyhydroxyalkanoates (PHAs) due to their comprehensive capability. In this study, a microbial consortium consisting of Pseudomonas putida NBRC14164 and Saccharomyces cerevisiae SyBE_Sc01020078 was constructed where xylose was converted into nutrients utilizable to P. putida by S. cerevisiae to realize the production of medium‐chain‐length polyhydroxyalkanoates (mcl‐PHAs) from xylose and octanoate, followed by a preliminary analysis of the interaction between the two strains. The optimal inoculation ratio consisted of 1% P. putida and 10% S. cerevisiae, and both strains exhibited the highest PHA production at their mid‐exponential phase. The two microorganisms were grown in a mineral salt medium with xylose and octanoate as substrates without washing and cultured at 200 rpm. The mcl‐PHA titre of this consortium was 295.7 mg/L, which was 150% higher than that of P. putida in pure culture. Metabolites analysis by gas chromatography–mass spectrometry revealed metabolic communication between P. putida and S. cerevisiae, whereby the former provided histidine, methionine, and leucine for the latter, while the latter converted xylose into lactic acid, which is a more accessible carbon source for the former. [ABSTRACT FROM AUTHOR]

Water‐soluble and air‐stable gold nanoparticles stabilized by a xyloside‐based ligand containing a pyridine ring‐functionalized 1,2,3‐triazole backbone were prepared in the presence of a reducing agent. During their preparation, UV‐vis and NMR spectroscopic techniques were used to study the interaction between the xyloside ligand and Au(III) ions. These AuNPs were characterized by UV‐vis spectroscopy, TEM and DLS and showed a small size (average diameter<10 nm determined by TEM). Their catalytic activity was tested in the reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in water. [ABSTRACT FROM AUTHOR]

Waste accumulation is a grave concern and becoming a transboundary challenge for environment. During Covid‐19 pandemic, diverse type of waste were collected due to different practices employed in order to fight back the transmission rate of the virus. Covid‐19 was proved to be capricious catastrophe of this 20th century and even not completely eradicated from the world. The havoc created by this imperceptible quick witted, pleomorphic deadly virus can't be ignored. Though a number of vaccines have been developed by the scientists but there is a fear of getting this virus again in our life. Medical studies prove that immunity drinks will help to reduce its reoccurrences. Coconut water is widely used among all drinks available globally. Its massive consumption created an incalculable pile of green coconut shells around the different corners of the world. This practice generating enormous problem of space acquisition for the environment. Both the environment and public health will benefit from an evaluation of quantity of coconut waste that is being thrown and its potential to generate value added products. With this context, present article has been planned to study different aspects like, coconut waste generation, its biological properties and environmental hazards associated with its accumulation. Additionally, this review illustrates, green technologies for production of different value added products from coconut waste. [ABSTRACT FROM AUTHOR]

Xylose‐rich undefined broth, extracted from the dilute acid pretreatment wastes of barley straw, serves as resourceful media for Acremonium chrysogenum M35 culture and production of cephalosporin C (CPC). Concentrating the extract with proper reprocessing enables to prepare various concentrations of xylose broth (2%–8%). The undefined xylose media were prepared for CPC production from A. chrysogenum M35 by the addition of other nutrients. Cell growth and CPC production were the most effective at 6% xylose and additional 2% glycerol, with maximum CPC production of 9.07 g/L after 6 days, which is higher production than that in defined media prepared with laboratory‐level nutrients and reagents. Investigation of autotrophic and reverse trans‐sulfuration pathways for cysteine synthesis, a limited element of three precursors for CPC synthesis, supports the enhanced CPC production in undefined media. Abundance of xylose ensures a maintained NADPH concentration required for sulfate reduction and synthesis of amino sulfide such as cysteine. Cystathionine‐γ‐lyase activity profiling indicated more efficient biosynthesis in undefined media than in other cultures use glycerol and glucose, and the biosynthesis pathway of CPC production by the cephalosporin gene cluster (i.e. pcbC and cefG genes) was investigated. The process using undefined xylose media was designed, and process simulation program confirmed our results. [ABSTRACT FROM AUTHOR]

A series of bifunctional P‐Zr‐SBA‐15 catalysts with Lewis acid and Brønsted acid sites were prepared by modifying mesoporous material SBA‐15 with Zr4+ and phosphate group, which were used in the conversion of xylose and xylan into furfural. The structure and acidic characteristics of the catalyst were analyzed by X‐ray diffraction, Fourier transform infrared spectroscopy, N2 adsorption desorption, scanning/transmission electron microscopy, X‐ray photoelectron spectroscopy, thermogravimetric analysis, NH3 temperature programmed desorption, and pyridine adsorption infrared spectroscopy. The effects of different process parameters on the catalytic performance of the catalyst were studied. when using the xylose and xylan as substrates, the furfural yield were 80.3 % and 68.8 % under the optimal conditions in the H2O(NaCl)/toluene (3/3 mL) biphasic solvent system, respectively, and 52.5 % furfural yield was obtained using xylose as substrate in aqueous system. In addition, the catalyst has good thermal stability and easy recovery in the recycling experiment. [ABSTRACT FROM AUTHOR]

Background: Seabuckthorn fruits contains many active subtances, among them, the seabuckthorn polysaccharide is one of the main active ingredients, and exhibits diverse bioactivities. The extraction of polysaccharides from seabuckthorn fruits is the most important step for their wide applications. Ultrasound‐assisted aqueous two‐phase extraction (UA‐ATPE) is a promising green method for extracting polysaccharides. Additionally, physicochemical characterization and antioxidant activities can evaluate the potential functions and applications in the food and medicine industries. Results: Based on the single‐factor experiments, 20.70% (w/w) ammonium sulfate ((NH4)2SO4) and 27.56% (w/w) ethanol were determined as the suitable composition for aqueous two‐phase. The optimum conditions of UA‐ATPE obtained by response surface methodology were as follows: ultrasonic power (390 W), extraction time (41 min), liquid‐to‐material ratio (72: 1 mL/g), and the total yield of the polysaccharides reached 34.14 ± 0.10%, The molecular weights of the purified upper‐phase seabuckthorn polysaccharide (PUSP) and the purified lower‐phase seabuckthorn polysaccharide (PLSP) were 65 525 and 26 776 Da, respectively. PUSP and PLSP contained the same six monosaccharides (galacturonic acid, rhamnose, xylose, mannose, glucose and galactose), but with different molar ratios. Furthermore, PUSP and PLSP displayed certain viscoelastic property, had no triple helical structure, possessed different thermal stability, surface morphology and conformation in aqueous solution. PUSP and PLSP displayed strong antioxidant properties by the assays of scavenging ability of ABTS+·, the protection of DNA damage and erythrocyte hemolysis. Conclusion: UA‐ATPE significantly increased the yield of seabuckthorn polysaccharides. PUSP and PLSP were different in many aspects, such as molar ratio, surface shape and antioxidant activities. Seabuckthornpolysaccharides possess great potential in medicine and functional foods. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In the face of increasing mobility and energy demand, as well as the mitigation of climate change, the development of sustainable and environmentally friendly alternatives to fossil fuels will be one of the most important tasks facing humankind in the coming years. In order to initiate the transition from a petroleum‐based economy to a new, greener future, biofuels and synthetic fuels have great potential as they can be adapted to already common processes. Thereby, especially synthetic fuels from CO2 and renewable energies are seen as the next big step for a sustainable and ecological life. In our study, we directly address the sustainable production of the most common biofuel, ethanol, and the highly interesting next‐generation biofuel, isobutanol, from methanol and xylose, which are directly derivable from CO2 and lignocellulosic waste streams, respectively, such integrating synthetic fuel and biofuel production. After enzyme and reaction optimization, we succeeded in producing either 3 g L−1 ethanol or 2 g L−1 isobutanol from 7.5 g L−1 xylose and 1.6 g L−1 methanol. In our cell‐free enzyme system, C1‐compounds are efficiently combined and fixed by the key enzyme transketolase and converted to the intermediate pyruvate. This opens the way for a hybrid production of biofuels, platform chemicals and fine chemicals from CO2 and lignocellulosic waste streams as alternative to conventional routes depending solely either on CO2 or sugars. [ABSTRACT FROM AUTHOR]

Cyclopentadiene (CPD) and methylcyclopentadiene (MCPD) are important intermediates that have been widely used in the production of high‐energy‐density rocket fuels, polymers and valuable chemicals. Currently, CPD and MCPD are produced from fossil energies at very low yields, which greatly limits their application. As a solution to this problem, we disclose an alternative two‐step bio‐route to access CPD and MCPD using xylose or extracted hemicellulose as the feedstock. In the first step, cyclopentanone (CPO) was directly produced by the selective hydrogenolysis of xylose or extracted hemicellulose over a commercial Ru/C catalyst in an acid‐free toluene/NaCl aqueous solution biphasic system. In the second step, CPO was selectively converted to CPD by a cascade hydrodeoxygenation/dehydrogenation reaction over zinc molybdate catalysts. When methanol was introduced with CPO and hydrogen, MCPD was selectively obtained by a cascade dehydrogenation/aldol condensation/selective hydrodeoxygenation reaction over zinc molybdate catalysts. [ABSTRACT FROM AUTHOR]

A short and convenient approach to the original xyloside‐based ligands, has been achieved, using d‐xylose as a starting material. The complexation properties of these ligands towards Au(III) cations were studied by different methods, such as multinuclear NMR, mass spectrometry, elemental analysis. A preliminary study using protometric titrations has been carried out in aqueous solution under various pH conditions, thus in order to investigate the binding of Au(III) cations to these ligands. Furthermore, molecular calculations were performed to obtain additional structural information. The catalytic activity of the most stable Au(III) complexes was evaluated for the homogeneous reduction of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) in the presence of NaBH4. [ABSTRACT FROM AUTHOR]

BACKGROUND: The fermentation valorization of two main lignocellulosic monosaccharides, glucose and xylose, is extensively developed; however, it is restricted by limited yield and process complexity. An in vitro enzymatic cascade reaction can be an alternative approach. RESULTS: In this study, a three‐stage, five‐enzyme cascade was developed to convert pretreated biomass to valuable chemicals. First, a ribose‐5‐phosphate isomerase B mutant isomerized xylose to d‐xylulose with high substrate specificity, and a d‐arabinose dehydrogenase continued to reduce d‐xylulose to d‐arabitol. Simultaneously, glucose was utilized for the coenzyme regeneration catalyzed by a glucose dehydrogenase, generating useful gluconic acid and achieving 73% of total conversion rate after 36 h. Then, six kinds of pretreated biomass lignocellulose were hydrolyzed by cellulase and hemicellulase, and corn cob was identified as the initial substrate for providing the highest monosaccharide content. A 65% conversion rate of the lignocellulosic xylose was obtained after 24 h. CONCLUSIONS: This study presents a proof of concept to convert main lignocellulosic monosaccharides systematically by an enzymatic cascade at stoichiometric ratio. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: A novel molecularly imprinted hydrogel (X‐MIP) was developed with poly (allylamine hydrochloride) as monomer and epichlorohydrin as crosslinker. After optimising preparation conditions including reaction temperature, the amount of NaOH and template xylose, the X‐MIP was characterised through Fourier transform infrared spectroscopy, scanning electron microscope and swelling ratio. Xylose and glucose were employed to evaluate the adsorption capacity and selectivity of the X‐MIP. Its adsorption to xylose followed pseudo‐second‐order rate kinetics and the adsorption process was multilayer adsorption based on the matched Freundlich isotherm model. Its adsorption capacity to xylose was up to 398.68 mg g−1. The similar adsorption abilities in five successive runs and the good desorption rate (98.9%) verified its reusability. The selectivity for xylose and glucose could reach 4.70, and their separation factors in simulated xylitol production feedstocks were 591.05 (xylose:glucose, 99:1) and 15.42 (xylose:glucose, 3:1), respectively. Results indicated the prepared X‐MIP has good potential in industrial xylose purification. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rare sugars have become promising 'sugar alternatives' because of their low calories and unique physiological functions. Among the family of rare sugars, d‐allulose is one of the sugars attracting interest. Ketose 3‐epimerases (KEase), including d‐tagatose 3‐epimerase (DTEase) and d‐allulose 3‐epimerase (DAEase), are mainly used for d‐allulose production. RESULTS: In this study, a putative xylose isomerase from Caballeronia insecticola was characterized and identified as a novel DAEase. Caballeronia insecticola DAEase displayed prominent enzymatic properties, and 150 g L−1d‐allulose was produced from 500 g L−1d‐fructose in 45 min with a conversion rate of 30% and high productivity of 200 g L−1 h−1. Furthermore, DAEase was employed in a phosphorylation–dephosphorylation cascade reaction, which significantly increased the conversion rate of d‐allulose. Under optimized conditions, the conversion rate of d‐allulose was approximately 100% when the concentration of d‐fructose was 50 mmol L−1. CONCLUSION: This research described a very beneficial and facile approach for d‐allulose production based on C. insecticola DAEase. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The National Renewable Energy Laboratory (NREL) published a model in 2017 that enables the minimum selling price of lignocellulosic sugar to be calculated. The model can be modified to suit any biomass feedstock and operational design. In the present case, the model is used to understand the economics of a process configuration that incorporates liquefaction as a preprocessing step in corn‐stover‐fed biorefinery. This study demonstrates a quantitative approach utilizing an existing biorefinery setup to simulate the biomass liquefaction technique while estimating the price of the resulting sugar product. The objective is to understand whether the addition of liquefaction methodology – and the substitution of acid pretreatment – can reduce the cost of lignocellulosic sugars. The reason for setting up a liquefaction unit at the start is to reduce the yield stress of biomass slurry so that the flow remains unrestricted downstream. The liquefaction process is also unique because it uses no chemicals and saves the cost of pretreatment. The pretreatment step is bypassed because the output of liquefaction can be fed into enzyme hydrolysis just after simple cooking. The liquefaction process can be performed in three modes: enzyme, enzyme mimetic, and a combination of enzyme and enzyme mimetic. The results from the BC1707 model indicate the minimum cost for the enzyme liquefaction route. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Carbon‐based solid acid catalysts (CS−SO3H) were prepared by one‐pot carbonization‐sulfonation method with concentrated sulfuric acid using cotton as raw material, which was used to transformation of xylose and corn cob to furfural. The catalyst preparation conditions were optimized to be that the cotton mass/sulfuric acid volume ratio is 1 : 20 (g/mL), and the reaction is carried out at 160 °C for 10 h. The morphology, functional groups and surface chemical state were investigated. The yield of furfural can reach 87.3 % from xylose under the optimal reaction condition of 0.1 g xylose, 0.05 g catalyst, 180 °C for 90 min in 5.0 mL γ‐valerolactone‐water solvent. The yield of furfural can reach 63.2 % by the direct one‐pot conversion of corn cob over the CS−SO3H under the optimal reaction condition of 0.1 g corn cob, 0.1 g catalyst, 190 °C for 90 min in 5.0 mL γ‐valerolactone‐water solvent. The catalytic activity gradually declined when it was cycled for four times. The reason was determined to be the partial shedding of the sulfonic acid groups grafted on the catalyst during the reaction and insoluble humus accumulated on the catalyst surface. After regeneration, the catalytic activity can be restored. [ABSTRACT FROM AUTHOR]

Next‐generation gene and engineered‐cell therapies benefit from incorporating synthetic gene networks that can precisely regulate the therapeutic output in response to externally administered signal inputs that are safe, readily bioavailable and pleasant to take. To enable such therapeutic control, a mammalian gene switch is designed to be responsive to the natural sweetener xylose and its functionality is assessed in mouse studies. The gene switch consists of the bacterial transcription regulator XylR fused to a mammalian transactivator, which binds to an optimized promoter in the presence of xylose, thereby allowing dose‐dependent transgene expression. The sensitivity of SWEET (sweetener‐inducible expression of transgene) is improved by coexpressing a xylose transporter. Mice implanted with encapsulated SWEET‐engineered cells show increased blood levels of cargo protein when taking xylose‐sweetened water or coffee, or highly concentrated apple extract, while they do not respond to intake of a usual amount of carrots, which contain xylose. In a proof‐of‐concept therapeutic application study, type‐1 diabetic mice engineered with insulin‐expressing SWEET show lowered glycemia and increased insulin levels when administered this fairly diabetic‐compliant sweetener, compared to untreated mice. A SWEET‐based therapy appears to have the potential to integrate seamlessly into patients' life‐style and food habits in the move toward personalized medicine. [ABSTRACT FROM AUTHOR]

Alkaliphiles are considered more suitable chassis than traditional neutrophiles due to their excellent resistance to microbial contamination. Alkaliphilic Bacillus sp. N16‐5, an industrially interesting strain with great potential for the production of lactic acid and alkaline polysaccharide hydrolases, can only be engineered genetically by the laborious and time‐consuming homologous recombination. In this study, we reported the successful development of a CRISPR/Cas9‐based genome editing system with high efficiency for single‐gene deletion, large gene fragment deletion and exogenous DNA chromosomal insertion. Moreover, based on a catalytically dead variant of Cas9 (dCas9), we also developed a CRISPRi system to efficiently regulate gene expression. Finally, this efficient genome editing system was successfully applied to engineer the xylose metabolic pathway for the efficient bioproduction of D‐lactic acid. Compared with the wild‐type Bacillus sp. N16‐5, the final engineered strain with XylR deletion and AraE overexpression achieved 34.3% and 27.7% increases in xylose consumption and D‐lactic acid production respectively. To our knowledge, this is the first report on the development and application of CRISPR/Cas9‐based genome editing system in alkaliphilic Bacillus, and this study will significantly facilitate functional genomic studies and genome manipulation in alkaliphilic Bacillus, laying a foundation for the development of more robust microbial chassis. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the effect of extrusion at high solid loading on corn stover (CS) properties and its enzymatic hydrolysis. This biomass was extruded under different screw speeds and different solid loadings and the impact of these parameters on the physicochemical properties was evaluated. It was found that lignocellulosic components were not significantly affected by the pretreatment, while the surface area increased with solid loading and rotation speed. Different enzyme cocktails were used for the enzymatic hydrolysis of extruded and untreated CS. Overall, mild twin‐extrusion enhanced the enzymatic hydrolysis of CS through an increase in glucose and xylose yields by 134–212% and 214–294%, respectively, when using Trichoderma longibrachiatum cellulase. The highest sugar content was obtained from CS extruded under 400 g total solids per liter and 200 rpm. The energy efficiency of the pretreatment was also assessed and was found to be maximal at 400 g total solids per liter and 200 rpm. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

BACKGROUND: Bulgur bran (BB) is a potential source for the production of value‐added products such as fermentable sugars and xylooligosaccharides (XOs). In this study, alkali combined twin‐screw extrusion pretreatment was performed and statistically optimized to enhance fractionation and enzymatic hydrolysis of BB. The pretreatment conditions (barrel temperature, screw speed and alkali impregnation) were optimized by Box–Behnken design (BBD) to obtain the highest hemicellulose separation from BB. The obtained fractions were analyzed for the production of fermentable sugars and XOs. RESULTS: The results revealed that twin‐screw extrusion of BB performed at 67 °C barrel temperature and 250 rpm screw speed after alkali impregnation at 0.02 g alkali g−1 biomass concentration provided 40.4% higher hemicellulose separation yield compared to the untreated BB. Alkali combined twin‐screw extrusion pretreatment increased the enzymatic hydrolysis yield of BB fourfold, whereas a 13‐fold increase was achieved after the separation of hemicellulose from pretreated BB. Xylose (X1)‐free xylobiose (X2) was the main product after xylanase hydrolysis of hemicellulose fraction. SEM images confirmed the morphological modifications in BB, which were in agreement with the enhanced fractionation performance and the higher enzymatic hydrolysis yield. CONCLUSION: The results of this study suggested that pretreatment by alkali combined twin‐screw extrusion followed by alkali extraction could be a reliable and effective process for fractionation of BB and production of fermentable sugars and XOs. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Using natural biomass as sacrificial agent for photocatalytic hydrogen production is a current topic of interest in the field of new energy research because it has widely available resources, is economical, and has environmental benefits. In this study, we propose a strategy for photocatalytic hydrogen production using acid‐treated corn straw and its extracts as a sacrificial agent. Furthermore, the important factors that affect the photocatalytic performance of hydrogen production are also studied. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) are employed to characterize the composition, structure, and morphology of the corn straw. High‐performance liquid chromatography (HPLC) is employed to characterize the composition of extracts in the filtrate obtained from acid treatment. The results from the above analyses show that cellobiose and xylose, which are extracted from corn straw, significantly improve the hydrogen production performance. The optimal hydrogen generation rates in this study reach 30.583 μmol/h in 100 mL of water; this is 72 times greater than that using pure water, 2 times greater than that using raw corn straw, and 4.5 times greater than that using acid‐treated corn straw. Also, from these characterizations and analyses, the possible photocatalytic mechanism of this system is also proposed in this paper. [ABSTRACT FROM AUTHOR]

Xylo‐oligosaccharide (XOS) can stimulate the growth of Bifidobacterium, it is widely used in functional food, nutritional products and other aspects. At present, XOS is mainly prepared by hydrolysis of the hemicellulose in plant materials by enzyme catalyzing, resulting the high cost. In order to find an efficient method to reduce the cost, XOS was prepared by synthesis from D‐xylose through oxalate acid catalyzing in this paper, getting the results as following: a light‐yellow product of XOS was obtained with the max yield of 53.75±3.48 %. Its molecular weight is in the range of 459–1306 g/mol, being oligomers contain 3–9 units of D‐xylose units. In addition, the XOS contains both of the basic units of α‐D‐xylose and β‐D‐xylose, mainly connected by both α1‐β4 and β1‐α4 glycosidic bonds. Therefore, this study develops a new method of XOS generation, doing benefit to the high value‐added utilization of xylose. [ABSTRACT FROM AUTHOR]

Efficient synthesis of furfural from xylose over the HCl catalyst in a water‐methyl isobutyl ketone biphasic system was achieved in slug flow microreactors, using NaCl as a promotor which facilitates xylose dehydration and suppresses xylose condensation. An optimized furfural yield of 93% was obtained from 1 M xylose over 0.2 M HCl with 10 wt% NaCl at 180°C within 4 min. A comprehensive kinetic model was developed from monophasic experiments in water in microreactors, by incorporating the acidity in water and kinetic constants as a function of the chloride ion concentration. The coupling of kinetic model with furfural extraction, with consideration of phase volume change as a function of temperature and partial phase miscibility, enables to predict the results of biphasic experiments in microreactors where mass‐transfer limitation was eliminated. The aqueous phase containing HCl and NaCl could be readily recycled and reused multiple times without noticeable performance loss. [ABSTRACT FROM AUTHOR]

BACKGROUND The present study has revealed an innovative method of coupling enzyme hydrolysis, yeast fermentation and thermal treatment to transform pork trimmings into a seasoning product. The pork trimmings were first enzymatically hydrolysed and fermented into liquid pork hydrolysates, followed by adding xylose and cysteine, then heat treatment. RESULTS: Approximately 28% of xylose and 7% of glucose were consumed, and amino acids increased by around 31% after thermal treatment. The heated yeast fermented pork hydrolysates possessed a characteristic 'savoury, roasted‐meat and fruity sweet' aroma as a result of the formation of thermally induced sulfur‐containing volatiles such as 2‐furfurylthiol, as well as retention of yeast generated esters including isoamyl acetate and hexyl acetate. CONCLUSION: The heat‐treated fermented pork hydrolysates impart an attractive and innovative aroma because of yeast fermentation and heat treatment. The innovative heated fermented pork hydrolysates could be further processed into a nutritional and savoury pork broth and/or a meat sauce. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: We proposed a novel phenomic approach to track the effect of short‐term exposures of Lactiplantibacillus plantarum and Leuconostoc pseudomesenteroides to environmental pressure induced by brewers' spent grain (BSG)‐derived saccharides. Water‐soluble BSG‐based medium (WS‐BSG) was chosen as model system. The environmental pressure exerted by WS‐BSG shifted the phenotypes of bacteria in species‐ and strains‐dependent way. The metabolic drift was growth phase‐dependent and likely underlay the diauxic profile of organic acids production by bacteria in response to the low availability of energy sources. Among pentosans, metabolism of arabinose was preferred by L. plantarum and xylose by Leuc. pseudomesenteroides as confirmed by the overexpression of related genes. Bayesian variance analysis showed that phenotype switching towards galactose metabolism suffered the greatest fluctuation in L. plantarum. All lactic acid bacteria strains utilized more intensively sucrose and its plant‐derived isomers. Sucrose‐6‐phosphate activity in Leuc. pseudomesenteroides likely mediated the increased consumption of raffinose. The increased levels of some phenolic compounds suggested the involvement of 6‐phospho‐β‐glucosidases in β‐glucosides degradation. Expression of genes encoding β‐glucoside/cellobiose‐specific EII complexes and phenotyping highlighted an increased metabolism for cellobiose. Our reconstructed metabolic network will improve the understanding of how lactic acid bacteria may transform BSG into suitable food ingredients. [ABSTRACT FROM AUTHOR]

Summary: The objective of this study was to evaluate the effectiveness of using enzymatic hydrolysis and microbial fermentation coupled with thermal treatment methods in valorising a type of industrially generated meat by‐product: pork trimmings, so as to produce a value‐added meat‐based flavouring. The pork trimmings were first hydrolysed using a protease (Flavourzyme) under optimised conditions and then fermented into liquid hydrolysates with mixed Lactobacillus fermentum and Pichia kluyveri; afterwards, xylose and cysteine were added to the fermented hydrolysates for heat treatment. A characteristic "savoury and roasted‐meat" aroma was produced due to the formation of potent sulphur‐containing volatile compounds such as 2‐furfurylthiol and methionol, though the browning intensity was inhibited due to the presence of cysteine. The thermal treatment did not significantly affect the fruity and sweet‐smelling ester volatiles such as isoamyl acetate and hexyl acetate that resulted from microbial fermentation. The decreases of amino acids and xylose might be due to their active participation in the Maillard reaction. The produced pork hydrolysates that imparted a unique aroma could be applied as a flavour enhancer or seasoning in the food industry. [ABSTRACT FROM AUTHOR]

Polyurethanes are widely used in daily life, from the textile industry to medical applications. In this study, a biocompatible and transparent coating from polyethylene glycol‐based polyurethanes including different type of saccharide (xylose as monosaccharide, sucrose as disaccharide, or starch as polysaccharide) is prepared. Prepared optically transparent polyurethanes are characterized with different instrumental analysis techniques and contact‐angle measurements. Thermogravimetric analysis data allow understanding that the synthesized saccharide based polyurethanes are resistant to high temperatures, which means that medical devices can be easily coated with one of the saccharide‐based polymers during the manufacturing process. The study results also show that synthesized polyurethane samples having a different kind of saccharides present high biocompatibility and transparency properties via In vitro cytotoxicity analysis and optic transparency tests. For xylose, sucrose, or starch containing polyurethanes, the tranmittance values are 97.72%, 85.20%, and 89.23%, respectively. In addition, scanning electron microscope images show that the samples also have smooth surfaces which can be used for proper coating of medical devices. Consequently, this manuscript addresses synthesis and characterization of the optically transparent polyurethanes based on specific saccharides for biocompatible and transparent surfaces especially in optic medical devices such as colonoscopy applications and laparoscopic detection probes. [ABSTRACT FROM AUTHOR]

The EU's bioeconomy strategy has a strong commitment to the development of biotechnological approaches to convert municipal solid biowastes into value‐added products. In this context, the current study investigated the thermophilic co‐fermentation of pruning lignocellulosic and food wastes to co‐produce hydrogen and carboxylic acids. Steam explosion pretreatment considerably enhanced the chemical oxygen demand (COD) solubilization reaching values up to 80% even with high lignocellulosic waste content. Acidification yield in terms of COD was strongly dependent on thermal pretreatment, varying from 20–30% up to ca. 60% with thermal pretreatment of the mixed urban waste. Under the best tested conditions, thermophilic co‐fermentation produced up to 162 ± 5 mlH2 gCOD−1. This hydrogen production decreased notably with the increase in the lignocellulosic fraction in the feed, the effect being stronger in the absence of thermal treatment. The results clearly showed a positive synergy effect in the overall efficiency of acidogenic fermentation and the strong dependence of carboxylic acid distribution on the initial composition of the feed. Values up to 0.58 gCOD of carboxylic acids per gCOD added were achieved with thermal pretreatment of the mixed urban waste, resulting in 93% acidification. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

Hydrothermal processing is an organic solvent‐free technology capable of solubilizing hemicellulose in oligomers of interest. This study evaluated the influence of pressure (2.5 and 10 MPa) on the release of the main components of sugarcane bagasse (SCB) as reducing sugars, phenolic compounds and xylooligosaccharides (XOS) during hydrothermal treatment in a continuous flow mode for 30 min. The study carried out at 180°C showed that 85% of the sugar extraction capacity was reached after 15 min at both pressures. The evolution of pH, phenolic compounds released in the liquor and small changes in the lignocellulosic structure were also monitored and related to the effects of hydrothermal treatment. The xylose content was similar at both pressures (22 mg/g xylan), while the XOS (X2‐X6) yield was 87.5 and 111.4 mg/g xylan at 2.5 and 10 MPa, respectively. A mass balance was used to estimate that 6.76 kg of XOS could be produced from 100 kg of SCB treated at 180°C, 2.5 MPa, and 15 min. Practical Applications: Sugarcane production generates a large amount of by‐products. The study aimed to use sugarcane bagasse (SCB) for the extraction of xylooligosaccharides through hydrothermal processing whose the influence of two pressures (2.5 and 10 MPa) in this process was evaluated. This process is an organic solvent‐free technology that establishes a sustainable strategy for the exploitation of this material. Residues (SCB) have great potential to be explored to prepare value‐added products in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The electroreforming of glucose/xylose mixtures has been evaluated at Pd1‐xAux/C anodes in 0.10 mol L−1 NaOH electrolyte. The catalysts synthesized by a wet chemistry route are comprehensively characterized by physicochemical and electrochemical techniques. From linear scan voltammetry and in situ Fourier transform infrared spectroscopy measurements, it was shown that the Pd0.3Au0.7/C material led to the best electrocatalytic behavior towards the electrooxidation of glucose/xylose mixtures in terms of activity (higher current densities at lower potentials) and selectivity (lower dissociative adsorption). Six‐hour chronoamperometry measurements were performed at 293 K in a 25 cm2 electrolysis cell at +0.4 V and +0.6 V and the reaction products were analyzed by high performance liquid chromatography. The main products were gluconate and xylonate, but the contributions of xylose to all formed products was always lower in percentages than the initial xylose ratios in solutions, showing that glucose was more electro‐reactive than xylose at Pd0.3Au0.7 surface. [ABSTRACT FROM AUTHOR]

d‐Xylose is a special monosaccharide found in various organisms, which is characterized by conformational dynamics between different pyranose ring forms depending on the substitution pattern. With a perspective to study the conformational equilibria of xylosides and eventually use them as conformational switches, we sought an entry into a flexible synthesis of 2,4‐diamino‐xylosides. In particular, we synthesized 4‐bromophenyl 2,4‐diamino‐3‐O‐(4‐bromophenyl)‐β‐d‐xyloside from l‐arabinose utilizing a concomitant epimerization and differentiation at position 4 and iodosulfonamidation of a difunctional xylal at a later stage of the synthetic pathway. This strategy provides xylose derivatives with high stereochemical precision and a high degree of functionalization. The obtained xylose derivatives are of interest as conformational hinge molecules and as orthogonally protected triamino scaffold molecules. [ABSTRACT FROM AUTHOR]

Atomically dispersed transition metal‐nitrogen‐carbon catalysts are emerging as low‐cost electrocatalysts for the oxygen reduction reaction in fuel cells. However, a cost‐effective and scalable synthesis strategy for these catalysts is still required, as well as a greater understanding of their mechanisms. Herein, iron, nitrogen co‐doped carbon spheres (Fe@NCS) have been prepared via hydrothermal carbonization and high‐temperature post carbonization. It is determined that FeN4 is the main form of iron existing in the obtained Fe@NCS. Two different precursors containing Fe2+ and Fe3+ are compared. Both chemical and structural differences have been observed in catalysts starting from Fe2+ and Fe3+ precursors. Fe2+@NCS‐A (starting with Fe2+ precursor) shows better catalytic activity for the oxygen reduction reaction. This catalyst is studied in an anion exchange membrane fuel cell. The high open‐circuit voltage demonstrates the potential approach for developing high‐performance, low‐cost fuel cell catalysts. [ABSTRACT FROM AUTHOR]

3,4‐Dihydroxybenzoate (protocatechuate, PCA) is a phenolic compound naturally found in edible vegetables and medicinal herbs. PCA is of high interest in the chemical industry and has wide potential for pharmaceutical applications. We designed and constructed a novel Corynebacterium glutamicum strain to enable the efficient utilization of d‐xylose for microbial production of PCA. Shake flask cultivation of the engineered strain showed a maximum PCA titer of 62.1 ± 12.1 mM (9.6 ± 1.9 g L−1) from d‐xylose as the primary carbon and energy source. The corresponding yield was 0.33 C‐mol PCA per C‐mol d‐xylose, which corresponds to 38% of the maximum theoretical yield. Under growth‐decoupled bioreactor conditions, a comparable PCA titer and a total amount of 16.5 ± 1.1 g PCA could be achieved when d‐glucose and d‐xylose were combined as orthogonal carbon substrates for biocatalyst provision and product synthesis, respectively. Downstream processing of PCA was realized via electrochemically induced crystallization by taking advantage of the pH‐dependent properties of PCA. This resulted in a maximum final purity of 95.4%. The established PCA production process represents a highly sustainable approach, which will serve as a blueprint for the bio‐based production of other hydroxybenzoic acids from alternative sugar feedstocks. [ABSTRACT FROM AUTHOR]

BACKGROUND: Aldo‐keto isomerizations of D‐xylose and D‐glucose catalyzed by xylose isomerase (XI) is commercially carried out to produce bio‐ethanol and high fructose corn syrup. XI is a metalloenzyme. In this paper, kinetics and thermodynamics of the activity and stability of hyperthermophilic recombinant XI from Thermotoga naphthophila RKU‐10T (TnapXI) were studied in the presence and absence of metal ions. RESULTS: Kinetics parameters of recombinant XI from TnapXI were calculated as Km = 0.99 mmol L–1, Vmax = 500 μmol.mg−1.min−1, and kcat = 68.3 min−1 for the isomerization of D‐xylose(aldo)⇌D‐xylulose(keto), whereas for D‐glucose(aldo)⇌D‐fructose(keto) conversion Km = 7.72 mmol L–1, Vmax = 90 μmol.mg−1.min−1, and kcat = 12.4 min−1. Ionization constants were calculated as pKa1 = 6.0 and pKa2 = 7.6, whereas activation constants (Ka) of TnapXI were 0.3, 0.5, and 4.0 mmol L–1 for Co2+, Mn2+, and Mg2+, respectively. Inhibition constant (Ki) was 0.119 mmol L–1 for Ca2+. Q10 was 2.8 and Ea = 82.25 kJ.mol−1. Thermodynamics for isomerization were calculated as ∆H* = 79.2 kJ.mol−1, ∆G* = 83 kJ.mol−1, and ∆S* = −10.5 J.mol−1.K−1. The z‐value was 12.6 °C for apo‐TnapXI and 32.6 °C for holo‐TnapXI. Deactivation parameters were ∆G*(d) = 100 kJ.mol−1, ∆H*(d) = 206 kJ.mol−1, ∆S*(d) = 0.28 kJ.mol−1.K−1 for apo‐TnapXI and t1/2 = 18 min at 95 °C, while ∆G*(d) = 104 kJ.mol−1, ∆H*(d) = 767 kJ.mol−1, ∆S*(d) = 1.8 kJ.mol−1.K−1 for holo‐TnapXI and t1/2 = 65 min at 95 °C. CONCLUSION: These noteworthy features make this enzyme an attractive candidate for the industrial production of fuel ethanol and high fructose corn syrup at high temperatures to maximize the product yield. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]