Semirational Design of a UDP-Glycosyltransferase from for Efficient Biosynthesis of Rebaudioside M2.

Rebaudioside M2 (RebM2) is characterized as 13-[(2--β-d-glucopyranosyl-3--β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(2--β-d-glucopyranosyl-6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester], an isomer of rebaudioside M with a 1 → 6 sugar linkage. The product was found in the biotransformation of rebaudioside D (RebD) catalyzed by a glycosyltransferase from (UGT). Herein, guided by consensus engineering and molecular dynamics simulations, a variant UGT with enhanced activity and thermostability was obtained.

Engineering an Ancestral Glycosyltransferase for Biosynthesis of 2-Phenylethyl-β-d-Glucopyranoside and Salidroside.

Phenylethanoid glycosides (PhGs) are naturally occurring glycosides derived from plants with various biological activities. Glycosyltransferases catalyze the production of PhGs from phenylethanols via a transglycosylation reaction. The low activity and stability of glycosyltransferase limit its industrial application.

Engineering UDP-Glycosyltransferase UGTPg29 for the Efficient Synthesis of Ginsenoside Rg3 from Protopanaxadiol.

Rare ginsenosides Rg3 and Rh2, which exhibit diverse pharmacological effects, are derivatives of protopanaxadiol (PPD). UDP-glycosyltransferases, such as the M315F variant of Bs-YjiC (Bs-YjiCm) from Bacillus subtilis and UGTPg29 from Panax ginseng, can efficiently convert PPD into Rh2 and Rh2 into Rg3, respectively. In the present study, the N178I mutation of Bs-YjiCm was introduced, resulting in an increase in Rh2 production.

Identification of sucrose synthase from to favor biocatalytic glycosylation.

Sucrose synthase (SuSy, EC 2.4.1.

Electroactive microorganisms synthesizing iron sulfide nanoparticles for enhanced hexavalent chromium removal in microbial fuel cells.

Microbial fuel cells (MFCs) have been considered a promising technology for Cr removal, but they are limited by Cr-reducing biocathodes with low extracellular electron transfer (EET) and poor microbial activity. In this study, three kinds of nano-FeS hybridized electrode biofilms, obtained through synchronous biosynthesis (Sy-FeS), sequential biosynthesis (Se-FeS) and cathode biosynthesis (Ca-FeS), were applied as biocathodes for Cr removal in MFCs. The Ca-FeS biocathode exhibited the best performance due to the superior properties of biogenic nano-FeS (e.

Three Glycosyltransferase Mutants in a One-Pot Multi-enzyme System with Enhanced Efficiency for Biosynthesis of Quercetin-3,4'--diglucoside.

Quercetin-3,4'--diglucoside (Q3,4'G), among the major dietary flavonoids, is superior to quercetin aglycone or quercetin monoglucoside in solubility. However, its low content in nature makes it hard to be prepared in large quantities by traditional extraction methods. In the present study, the F378S mutant of UGT78D2 (78D2_F378S) derived from with improved regioselectivity and the V371A mutant of UGT73G1 (73G1_V371A) derived from were adopted to realize a two-step continuous glycosylation of quercetin to produce Q3,4'G.

Improved performance of Cr(vi)-reducing microbial fuel cells by nano-FeS hybridized biocathodes.

Biocathode microbial fuel cells (MFCs) show promise for Cr(vi)-contaminated wastewater treatment. However, biocathode deactivation and passivation caused by highly toxic Cr(vi) and nonconductive Cr(iii) deposition limit the development of this technology. A nano-FeS hybridized electrode biofilm was fabricated by simultaneously feeding Fe and S sources into the MFC anode.

[Engineering and process management-based design of Comprehensive Biotechnology Experiment course].

Based on the demand of enterprise talents and the characteristics of manufacturing process management in biotechnology, in order to make the students acquire the ability to solve complex engineering problems in the production process, we developed a "Comprehensive Biotechnology Experiment" course, where two-step enzymatic production of l-aspartate and l-alanine were the key processes. In this course, we drew lessons from the site management of the production enterprise, performed the experimental operation mode of four shifts and three operations. The content of this course includes principles, methods and experimental techniques of several core curricula and the site management mode of enterprises.

The rapid high-throughput screening of ω-transaminases via a colorimetric method using aliphatic α-diketones as amino acceptors.

ω-Transaminases (ω-TAs) are widely available for the production of chiral amines and unnatural amino acids. Herein, a rapid spectrophotometric method was developed for screening ω-TAs based on the colored products that can be generated from transamination reactions between aliphatic α-diketones and amino donors catalyzed by ω-TAs. The possible mechanism of the formation of the colored product was investigated according to LC-Q-TOF-MS analysis.

Screening UDP-Glycosyltransferases for Effectively Transforming Stevia Glycosides: Enzymatic Synthesis of Glucosylated Derivatives of Rubusoside.

Five plant-derived uridine diphosphate glycosyltransferases (UGTs) that catalyzed the glucosylation of stevia glycosides (SGs) were uncovered as the result of sequence mining considering the catalytic residues and conserved motifs of the known UGTs. Thereinto, UGT from with high activity toward rubusoside has been enzymatically characterized. The recombinant UGT was demonstrated to catalyze the β-1,6-glucosylation at C19 of rubusoside, producing a monoglucosyl derivative 13-[(-β-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester], which was then submitted to a β-1,2-glucosylation by UGT, resulting in a diglucosyl derivative 13-[(-β-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(2--β-d-glucopyranosyl-6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester].

Efficient Production of 2-O-α-D-Glucosyl Glycerol Catalyzed by an Engineered Sucrose Phosphorylase from Bifidobacterium longum.

2-O-α-D-Glucosyl glycerol (2-αGG) can be used as a multipurpose anti-aging, cell-stimulating, and skin moisturizing agent in the cosmetic industry. Sucrose phosphorylase (SPase) has been widely used in the production of 2-αGG. In this paper, the gene encoding sucrose phosphorylase from Bifidobacterium longum (BlSP) was inserted into pRSF-Duet-1 to construct the recombinant plasmid pRSF-BlSP and was functionally expressed in E.

Dissolution behavior of arabinoxylan from sugarcane bagasse in tetrabutylammonium hydroxide aqueous solution.

Arabinoxylan is one of the main components of xylan-rich hemicellulose of sugarcane bagasse. The study on the dissolution behavior of arabinoxylan from sugarcane bagasse (AXSB) is beneficial to its efficient utilization. The dissolution behavior of AXSB in a 50% TBAH aqueous solution was investigated by small angle X-ray scattering and rheological methods.

N-acyl-homoserine lactones in extracellular polymeric substances from sludge for enhanced chloramphenicol-degrading anode biofilm formation in microbial fuel cells.

Exploring an efficient acclimation strategy to obtain robust bioanodes is of practical significance for antibiotic wastewater treatment by bioelectrochemical systems (BESs). This study investigated the effects of two acclimation conditions on chloramphenicol (CAP)-degrading anode biofilm formation in microbial fuel cells (MFCs). The one was continuously added the extracellular polymeric substances (EPS) extracted from anaerobic sludge and increasing concentrations of CAP after the first start-up phase, while the other was added the EPS-1 (N-acyl-homoserine lactones, namely AHLs were extracted from the EPS) at the same conditions.

Biocatalytic synthesis of 2-O-α-D-glucopyranosyl-L-ascorbic acid using an extracellular expressed α-glucosidase from Oryza sativa.

Background: 2-O-α-D-Glucopyranosyl-L-ascorbic acid (AA-2G) is an important derivative of L-ascorbic acid (L-AA), which has the distinct advantages of non-reducibility, antioxidation, and reproducible decomposition into L-AA and glucose. Enzymatic synthesis is a preferred method for AA-2G production over alternative chemical synthesis owing to the regioselective glycosylation reaction. α-Glucosidase, an enzyme classed into O-glycoside hydrolases, might be used in glycosylation reactions to synthesize AA-2G.

Identification, Characterization, and Site-Specific Mutagenesis of a Thermostable ω-Transaminase from .

In the present study, we have identified an ω-transaminase (ω-TA) from from the genome database by using two ω-TA sequences (ATA117 Arrmut11 from KNK168 and amine transaminase from NIH2624) as templates in a BLASTP search and motif sequence alignment. The protein sequence of the ω-TA from (TA) shows 38% sequence identity to that of ATA117 Arrmut11. The gene sequence of TA was inserted into pRSF-Duet1 and functionally expressed in BL21(DE3).

Effects of granular activated carbon and temperature on the viscosity and methane yield of anaerobically digested of corn straw with different dry matter concentrations.

Anaerobic digestion (AD) systems with high substrate concentrations are characterized by high viscosity, which affects material and energy transfer efficiencies, thereby influencing methane production efficiency. In this study, adding granular activated carbon (GAC) and increasing the temperature decreased the viscosity by 4.56-10.

Expression, Characterization and Its Deinking Potential of a Thermostable Xylanase From CHR43.

Genome mining is more and more widely used in identifying new enzymes from database. In the present study, we reported a putative xylanase, Pg-Xyn (WP_053166147.1), which originated from a psychrotolerant strain CHR 43, and was identified from Genbank by genome mining.

Discovering and efficiently promoting the extracellular secretory expression of Thermobacillus sp. ZCTH02-B1 sucrose phosphorylase in Escherichia coli.

Sucrose phosphorylase (SPase, EC2.4.1.

A novel core-shell Fe@Co nanoparticles uniformly modified graphite felt cathode (Fe@Co/GF) for efficient bio-electro-Fenton degradation of phenolic compounds.

In this study, a core-shell Fe@Co nanoparticles uniformly modified graphite felt (Fe@Co/GF) was fabricated as the cathode by one-pot self-assembly strategy for the degradation of vanillic acid (VA), syringic acid (SA), and 4-hydroxybenzoic acid (HBA) in the Bio-Electro-Fenton (BEF) system. The Fe@Co/GF cathode showed dual advantages with excellent electrochemical performance and catalytic reactivity not only due to the high electron transfer efficiency but also the synergistic redox cycles between Fe and Co species, both of which significantly enhanced the in situ generation of HO and hydroxyl radicals (OH) to 152.40 μmol/L and 138.

Coordinated response of Au-NPs/rGO modified electroactive biofilms under phenolic compounds shock: Comprehensive analysis from architecture, composition, and activity.

Electroactive biofilms (EABs) can be integrated with conductive nanomaterials to boost extracellular electron transfer (EET) for achieving efficient waste treatment and energy conversion in bioelectrochemical systems. However, the in situ nanomaterial-modified EABs of mixed-culture, and their response under environmental stress are rarely revealed. Here, two nanocatalyst-decorated EABs were established by self-assembled Au nanoparticles-reduced graphene oxide (Au-NPs/rGO) in mixed-biofilms with different maturities, then their multi-property were analyzed under long-term phenolic shock.

Bioconversion of Stevioside to Rebaudioside E Using Glycosyltransferase UGTSL2.

Rebaudioside E, one of the minor components of steviol glycosides, was first isolated and identified from Stevia rebaudiana in 1977. It is a high-intensity sweetener that tastes about 150-200 times sweeter than sucrose and is also a precursor for biosynthesis of rebaudioside D and rebaudioside M, the next-generation Stevia sweeteners. In this work, new unknown steviol glycosides were enzymatically synthesized from stevioside by coupling UDP-glucosyltransferase UGTSL2 from Solanum lycopersicum and sucrose synthase StSUS1 from Solanum tuberosum.

Biosynthesized iron sulfide nanoparticles by mixed consortia for enhanced extracellular electron transfer in a microbial fuel cell.

The bioanode of mixed consortia was for the first time used to in-situ synthesize iron sulfide nanoparticles in a microbial fuel cell (MFC) over a long-term period (46 days). These poorly crystalline nanoparticles with an average size of 29.97 ± 7.

Hydrolysis of Corncob Hemicellulose by Solid Acid Sulfated Zirconia and Its Evaluation in Xylitol Production.

Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.

Positive effects of concomitant heavy metals and their reduzates on hexavalent chromium removal in microbial fuel cells.

Cr(vi) laden wastewaters generally comprise a range of multiple heavy metals such as Au(iii) and Cu(ii) with great toxicity. In the present study, cooperative cathode modification by biogenic Au nanoparticles (BioAu) reduced from aqueous Au(iii) and Cu(ii) co-reduction were investigated for the first time to enhance Cr(vi) removal in microbial fuel cells (MFCs). With the co-existence of Cu(ii) in the catholyte, the MFC with carbon cloth modified with nanocomposites of multi-walled carbon nanotubes blended with BioAu (BioAu/MWCNT) obtained the highest Cr(vi) removal rate (4.

Enhancing biomethane production and pyrene biodegradation by addition of bio-nano FeS or magnetic carbon during sludge anaerobic digestion.

Pyrene exerts toxic effects on methanogens during anaerobic digestion of sludge, thus affecting the efficiency of sludge treatment. This study evaluated the facilitated direct interspecific electron transfer (DIET) between bacteria and methanogens when bio-nano FeS or magnetic carbon is added into anaerobic reactors. Results showed that adding 200 mg/L bio-nano FeS or magnetic carbon clearly reduced the accumulation of short-chain fatty acids and avoided acidification during 25 days of anaerobic digestion.