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N-methylated tryptamines, such as the hallucinogenic natural products, psilocybin and N,N-dimethyltryptamine (DMT), are gaining interest from the medical community due to their potential as next generation treatments for mental health disorders. The clinical relevance of these compounds has driven scientists to develop biosynthetic production routes to a number of tryptamine drug candidates, and efforts are ongoing to expand and further develop these biosynthetic capabilities. To that end, we have further characterized the substrate preferences of two enzymes involved in tryptamine biosynthesis: TrpM, a tryptophan N-methyltransferase from Psilocybe serbica, and PsiD, the gateway decarboxylase of the psilocybin biosynthesis pathway. Here, we show that TrpM can N-methylate the non-native amino acid substrate, 4-hydroxytryptophan, a key intermediate in the Escherichia coli-based recombinant psilocybin biosynthesis pathway. However, the ability to incorporate TrpM into a functional psilocybin biosynthesis pathway was thwarted by PsiD's inability to use N,N-dimethyl-4-hydroxytryptophan as substrate, under the culturing conditions tested, despite demonstrating activity on N-methylated and 4-hydroxylated tryptophan derivatives individually. Taken together, this work expands upon the known substrates for TrpM and PsiD, further increasing the diversity of tryptamine biosynthetic products., (© 2024 The Author(s). Biotechnology Progress published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.)

Butyl butyrate is a short-chain fatty acid ester (C8) with a fruity aroma. It has broad prospects in the fields of foods, cosmetics and biofuels. At present, butyl butyrate is produced by chemical synthesis in the industry, but it is highly dependent on petroleum-based products. The growing concerns regarding the future scarcity of fossil fuels have been strongly promoted the transition from traditional fossil fuels and products to renewable bioenergy and biochemicals. Therefore, it is necessary to develop a green biochemical technology to replace traditional petroleum-based materials. In recent years, microorganisms such as Escherichia coli and Clostridium have been engineered to serve as cell factories for the sustainable one-pot production of short-chain fatty acid esters, including butyl butyrate. This opinion highlights the recent development in the use of lipases and alcohol acyltransferases (AATs) for butyl butyrate production in microbial fermentation, as well as future perspectives., (© 2024 The Author(s). Microbial Biotechnology published by John Wiley & Sons Ltd.)

Parametric optimization always plays important roles in bioengineering systems to obtain a high product yield under the proper conditions. The parametric conditions of lactic acid production by homologous batch fermentation of Lactobacillus pentosus cells was optimized by the Box-Behnken design. The highest l-lactic acid yield was obtained as 0.836 ± 0.003 g/g glucose with the productivity of 0.906 ± 0.003 g/(L × H) under the optimum conditions of 34.7 °C, pH 6.2, 148 rpm agitation speed, and 9.3 g/L nitrogen source concentration determined by quadratic response surface with high accuracy. The adequate kinetic models of cell growth rate, lactic production rate, and glucose consumption rate were also established to describe the fermentation behavior of L. pentosus cells with the correlation coefficients of 09985, 0.9990, and 0.9989, respectively., (© 2020 International Union of Biochemistry and Molecular Biology, Inc.)

Lignocellulose, one of the most abundant renewable sources of sugar, can be converted into bioenergy through hydrolysis of cellulose and hemicellulose. Due to its renewability and availability in large quantities, bioenergy is considered as a possible alternative to fossil energy and attracts the attention of the world with increased concerns about environmental protection and energy crisis. The depolymerization of cellulosic substrate to monomer is the rate-limiting step in the bioconversion of lignocellulose by cellulolytic microbes. Cellulosome, a multienzyme complex from anaerobic cellulolytic bacteria, can efficiently degrade the cellulosic substrates. Previous studies have shown that the reconstitution of cellulosome in vitro and its heterologous expression or display on the cell surface can help to solve the low yield problem of cellulosome in cellulolytic bacteria. This paper reviews the research progress in the reconstitution of cellulosome as well as its application in biorefinery, including the construction of cellulosome as well as different methods for cellulosome reconstitution and its surface display. This review will promote the understanding of cellulosome and its reconstitution., (© 2019 International Union of Biochemistry and Molecular Biology, Inc.)

When using a combination of pre-extraction and chemical pulping, a high yield of sugar recovery and minimal negative effect on the subsequent pulping step are expected. In this work, the P factor was utilized to investigate the effect of auto-hydrolysis severity on sugar recovery, removal of the main component, and impact on the kraft pulping of acacia wood chips. Using a P factor of 235, 84.34% of the polysaccharides in 14.05 g L -1 of dissolved sugars could be obtained. In addition, the soluble sugars were easily separated with a recovery yield of 3.54 g ·L -1 and Mw of 4,690 g mol -1 by direct precipitation using organic solvents. However, a maximum of 22.14 g L -1 of dissolved sugars was obtained with approximately 72.53% polysaccharides and Mw of 2,198 g mol -1 for a P factor of 601. Moreover, nearly 50% of the degraded carbohydrates remained in the auto-hydrolyzed wood chips. The decrease in the mass of pentosan, holocellulose, and klason lignin was 62, 30, and 8.76%, respectively. With intensifying severity, the screened yield and viscosity of pulps decreased markedly, whileas the Kappa number increased. No significant differences were observed in the morphology of the resultant fibers. Moreover, there was a decrease in the physical strength of the pulps due to the loss of the intrinsic strength of the pulp fibers, which in turn resulted from the cellulose damage. The combustion performance of the resultant pulping black liquor is improved due to the higher lignin content., (© 2019 American Institute of Chemical Engineers.)

The main purpose of this study is to explore the sulfation of xylan to produce an anionic flocculant, sulfated xylan, for removing ethyl violet dye from simulated dye solutions. In this work, xylan was sulfated with chlorosulfonic acid in N, N-dimethylformamide solvent and the reaction conditions were optimized using a response surface methodology. It was observed that the maximum degree of substitution of 1.1 was obtained for sulfated xylan under the conditions of 3.71 chlorosulfonic acid/xylan molar ratio, 70°C and 7 h reaction time. The resulting sulfated xylan had a charge density of -3.12 mmol/g and molecular weight (M w ) of 22,300 g/mol. Furthermore, elemental and thermogravimetric analyses, Fourier transform infrared spectroscopy and proton nuclear magnetic resonance ( 1 H-NMR) confirmed the sulfation of xylan. The application of sulfated xylan as a flocculant for decolorizing the simulated ethyl violet dye wastewater was studied. The results indicated that 97% of dye was removed from 50 mg/L dye solution at the sulfated concentration of 175 mg/L and pH 9, but unmodified xylan was ineffective in flocculating and removing dye segments. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:529-536, 2018., (© 2018 American Institute of Chemical Engineers.)

This study investigated the impact of biomass-based fly ash (FA) pretreatment on the biodegradability of a thermomechanical pulping spent liquor (TMPL) in an aerobic system. In this study, FA was mixed with TMPL under the conditions of 6 wt.% based on TMPL, 25°C and 10 h, which removed a part of recalcitrant organic materials and resulted in 68.0, 40.0, 60.1, 81.2 and 48.3% reductions in chemical oxygen demand (COD), biochemical oxygen demand (BOD), total organic carbon (TOC), lignin and sugar, respectively. FA-pretreated TMPL pressate (FA-TMPL) was biologically treated in an aerobic system of sequencing batch reactor (SBR). The performance of the biological treatment with and without FA pretreatment was studied in two parallel SBRs over three months. The combination of FA and biological treatments removed 97.3% of COD, 98.3% of BOD, 96.3% of lignin, 99.5% of sugar, and 98.1% of TOC. Without FA pretreatment, the biological system removed 87.3% of COD, 89% of BOD, 81.6% of lignin, 98.6% of sugars, and 90.5% of TOC. The results also confirmed that the settling ability of sludge, which was indicated as a sludge volume index, was reduced from 109.3 mL/g to 53.5 mL/g. In addition, the advantages of using FA pretreatment in aerobic systems were discussed in detail. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:370-378, 2018., (© 2017 American Institute of Chemical Engineers.)

Among the protease-producing bacterial strains isolated from deep-sea sediments, SWJS2 was finally selected and identified as genus Exiguobacterium. Plackett-Burman and orthogonal array designs were applied to optimize the fermentation conditions, and the results are as follows: Glucose 5g, yeast extract 15g, glycerin 2g and CaCl2 ⋅2H2 O 0.5 g dissolved in 1 L artificial seawater; temperature 25 °C, original pH 7, inoculum rate 2%, seed age 12 H, loading volume 25 mL (250-mL Erlenmeyer flask), shaking speed 150 rpm, and fermentation time 44 H. The protease activity production was improved from about 80 to 660 U/mL under the optimized parameters. The protease was purified fourfold with specificity activity of 30,654.1 U/mg protein and a total yield of 16.2%. The protease exhibited the maximum activity at 40-45 °C and pH 7. Moreover, the enzyme activity was found to be inhibited by Cu(2+) , Ba(2+) , Cd(2+) , Hg(2+) , and Al(3+) at 5 mM, whereas it can be increased by Mg(2+) , Mn(2+) , and Ca(2+) at 0.5-5 mM. The enzyme was totally inactivated by 1 or 5 mM ethylenediaminetetraacetic acid but not by phenylmethanesulfonyl fluoride, tyrpsin inhibitor from Glycine max (STI), benzamidine, 5,5'-dithio-bis-(2-nitro benzoic acid), or pepstatin A, suggesting that it belonged to metalloprotease., (© 2015 International Union of Biochemistry and Molecular Biology, Inc.)

Potato residue is vastly produced in the food industry but it is landfilled. This article describes the treatment of purified cellulose derived from potato residues by a high pressure homogenizer to produce nano-fibrillated cellulose (NFC), which was then oxidized by sodium periodate to prepare dialdehyde nano-fibrillated cellulose (DANFC). The produced NFC and DANFC were characterized by a scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The orthogonal experiment was induced to obtain the maximum degree of oxidation (DO) on DANFC. The results indicated that the optimal conditions were 40°C and pH 3. Alternatively, the isotherm and kinetic studies for the adsorption of creatinine on DANFC with different DOs (70.5 and 88.8%) were investigated, and the experimental results fitted well into Freundlich isotherm model and pseudo second-order kinetic model. The maximum adsorption capacities of DANFCs with the DO of 70.55 and 88.85% were 6.7 and 17.2 mg g(-1) , respectively, which were achieved under the conditions of 37°C and initial creatinine concentration of 100 mg L(-1)., (© 2015 American Institute of Chemical Engineers.)

Enzymatic synthesis of ascorbyl undecylenate, an unsaturated fatty acid ester of ascorbic acid, was reported with biomass-derived 2-methyltetrahydrofuran (MeTHF) as the cosolvent. Of the immobilized lipases tested, Candida antarctica lipase B (CAL-B) showed the highest activity for enzymatic synthesis of ascorbyl undecylenate. Effect of reaction media on the enzymatic reaction was studied. The cosolvent mixture, t-butanol-MeTHF (1:4, v/v) proved to be the optimal medium, in which not only ascorbic acid had moderate solubility, but also CAL-B showed a high activity, thus addressing the major problem of the solvent conflict for dissolving substrate and keeping satisfactory enzyme activity. In addition, the enzyme was much more stable in MeTHF and t-butanol-MeTHF (1:4) than in previously widely used organic solvents, t-butanol, 2-methyl-2-butanol, and acetone. The much higher initial reaction rate in this cosolvent mixture may be rationalized by the much lower apparent activation energy of this enzymatic reaction (26.6 vs. 38.1-39.1 kJ/mol) and higher enzyme catalytic efficiency (Vmax /Km , 8.4 vs. 1.3-1.4 h(-1) ). Ascorbyl undecylenate was obtained with the yields of 84-89% and 6-regioselectivity of >99% in t-butanol-MeTHF (1:4) at supersaturated substrate concentrations (60 and 100 mM) after 5-8 h., (© 2014 American Institute of Chemical Engineers.)

Biobleaching of kraft pulp is a possible application of laccase, but it has not been described in detail for complete industrial bleaching sequences yet. Therefore, in this work, the biobleaching of Eucalyptus globulus kraft pulp was performed using a modified industrial totally chlorine-free sequence. The modification consisted in the substitution of an enzymatic delignification stage, based on the application of laccase from Trametes villosa, for the first alkaline extraction one. The enzymatic stage was performed with several synthetic and natural mediators, namely 1-hydroxybenzotriazole (HBT), violuric acid (VA), methyl syringate, and syringaldehyde. Several pulp properties were analyzed after each stage of the bleaching process--kappa number, ISO brightness, viscosity, and optical properties of CIEL*a*b* system. The new biobleaching sequence improved the pulp properties, in comparison to the conventional bleaching sequence, if HBT or VA was used as mediators. VA was selected as the best mediator of those tested and the effect of its concentration in the enzymatic stage was subsequently studied. Reducing the initial concentration by 30%, the same pulp quality was obtained, but if the reduction attained 60%, an important decrease in pulp integrity was detected. The modified bleaching sequence could improve the bleached pulp properties (kappa number 10%, ISO brightness 1%, and viscosity 5%) in comparison to the mill sequence., (Copyright © 2012 American Institute of Chemical Engineers (AIChE).)

The prehydrolysis liquor (PHL) of the kraft-based dissolving pulp production process contains various amounts of hemicelluloses that can be utilized in the production of value-added products. In this work, a new process was proposed for removing the inhibitors of PHL via employing a flocculation concept to facilitate the utilization of hemicelluloses. Lignin, lignocelluloses/cationic polymer complexes, and possibly ethanol are the main products of this process. This process has been experimentally evaluated with an industrially produced PHL and cationic polymers. The results showed that 16% of lignin, 19% of acetic acid, 43% of furfural, and insignificant amount of sugars were removed from PHL via pretreating PHL with acid and lime at pH 7. Furthermore, by adding 0.4-0.5 mg g(-1) polydiallyldimethylammonium chloride (PDADMAC) or chitosan to the pretreated PHL, 12-14% acetic acid, 40-50% furfural, 5-6% monomeric sugars, and 25% oligomeric sugars were removed from the PHL. The complexes made from these components may be applied as organic fillers in various industries. Alternatively, by adding 1.2 or 1.4 mg g(-1) PDADMAC or chitosan to the pretreated PHL, 30 or 35% of lignin was removed, respectively, which induced complexes that could be used as a fuel source. The composition of the complexes formed was also determined in this work., (Copyright © 2012 American Institute of Chemical Engineers (AIChE).)

The modular endoglucanase Cel9B from Paenibacillus barcinonensis is a highly efficient biocatalyst, which expedites pulp refining and reduces the associated energy costs as a result. In this work, we set out to identify the specific structural domain or domains responsible for the action of this enzyme on cellulose fibre surfaces with a view to facilitating the development of new cellulases for optimum biorefining. Using the recombinant enzymes GH9-CBD3c, Fn3-CBD3b, and CBD3b, which are truncated forms of Cel9B, allowed us to assess the individual effects of the catalytic, cellulose binding, and fibronectin-like domains of the enzyme on the refining of TCF kraft pulp from Eucalyptus globulus. Based on the physico-mechanical properties obtained, the truncated form containing the catalytic domain (GH9-CBD3c) has a strong effect on fibre morphology. Comparing its effect with that of the whole cellulase (Cel9B) revealed that the truncated enzyme contributes to increasing paper strength through improved tensile strength and burst strength and also that the truncated form is more effective than the whole enzyme in improving tear resistance. Therefore, the catalytic domain of Cel9B has biorefining action on pulp. Although cellulose binding domains (CBDs) are less efficient toward pulp refining, evidence obtained in this work suggests that CBD3b alters fibre surfaces and influences paper properties as a result., ((c) 2010 American Institute of Chemical Engineers)

This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180 degrees C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0-4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU beta-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus., ((c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.)

CAL-B-catalyzed synthesis of different 5'-O-monoester derivatives of 6-azauridine via a one-step highly regioselective enzymatic acylation route was successfully performed for the first time. The effects of some crucial factors on the enzymatic undec-10-enoylation of 6-azauridine were examined. The optimal reaction medium, molar ratio of 6-azauridine to vinyl undec-10-enoate and reaction temperature were found to be anhydrous acetone, 1:3 and 50 degrees C, under which the reaction rate, the substrate conversion and the regioselectivity were 22.3 mM/h, 99.0% and 99.0%, respectively. In addition, the enzyme recognition of acyl donors was investigated. The results showed that the enzyme activity varied widely with different acyl donors owing to the specific structure of the lipase active site and the acyl donors. 5'-O-Monoesters of 6-azauridine were achieved exclusively with all the acyl donors tested., (2009 American Institute of Chemical Engineers)

The effects of xylanase pretreatment of high lignin content softwood (SW) kraft pulp on subsequent pulp treatment with laccase in combination with gallic acid were investigated. Although xylanase pretreatment was ineffective in enhancing the laccase-facilitated biografting of gallic acid to kraft fibers, it was beneficial for subsequent treatment with laccase exclusively. Treating pulp fibers with xylanase followed by laccase provided a collective 25% and 46% increase in dry and wet tensile strength properties, respectively.

A laccase-mediator system (LMS) for biobleaching was applied to a bleached chemical pulp dyed with stilbene dye Direct Yellow 11. Of mediators tested, 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) was found to be more effective than either violuric acid (VA) or N-hydroxybenzotriazole (HBT), which had been shown to be superior to ABTS when bleaching virgin chemical pulp. The laccase-ABTS system removed more than 60% of the color.

Laccase was reacted with gallic acid in the presence of a high-kappa (91) kraft pulp. The result was a modified pulp with 34%, 20%, and 72% improvements in burst, tensile, and wet tensile strength compared to untreated control samples. Fully bleached pulps were not responsive to the laccase treatment, indicating lignin was the major target for the fiber modification. The results indicate that the strength increases were a combined effect of improvements of hydrogen bonding between fibers and creation of phenoxy radical cross-links within the sheet.