Strong and ductile cellulose film improved by the in situ incorporation of a genetically engineered protein conjugated synthetic polymer during bacterial cellulose growth.

Bacterial cellulose (BC) has been extensively applied to fabricate advanced biomaterials, although it remains challenging due to its poor toughness and water stability. Herein a genetically engineered protein-conjugated synthetic polymer is designed to improve BC film's strength and flexibility. Initially, the hybrid polymer is constructed by grafting Family 3 carbohydrate-binding modules (CBM3) to amphoteric polyacrylamide polymer (AmPAM), one of the paper industry's most widely used dry-strength agents.

Enhancing L-asparagine Production Through In Vivo ATP Regeneration System Utilizing Glucose Metabolism of Escherichia coli.

L-asparaginase synthetase, an ATP-dependent enzyme, necessitates ATP for its catalytic activity. However, the integration of L-asparaginase synthetase into industrial processes is curtailed by the prohibitive cost of ATP. To address this limitation, this study explores the construction of an efficient ATP regeneration system using the glucose metabolism of Escherichia coli, synergistically coupled with L-asparaginase synthetase catalysis.

Enhancing L-Asparagine Bioproduction Efficiency Through L-Asparagine Synthetase and Polyphosphate Kinase-Coupled Conversion and ATP Regeneration.

L-Asparagine, a crucial amino acid widely used in both food and medicine, presents pollution-related and side reaction challenges when prepared using chemical synthesis method. Although biotransformation methods offer significant advantages such as high efficiency and mild reaction conditions, they also entail increased costs due to the need for ATP supplementation. This study aimed to address the challenges associated with biopreparation of L-asparagine.

[Secretory expression and fermentation optimization for extracellular production of pullulanase in ].

Pullulanase is a starch debranching enzyme, which is difficult in secretory expression due to its large molecular weight. is a novel expression host with excellent efficiency in protein synthesis. In this study, we achieved secretory expression of the full-length pullulanase PulA and its truncated mutant PulN2 using .

Efficient secreted expression of natural intracellular β-galactosidase from Bacillus aryabhattai via non-classical protein secretion pathway in Bacillus subtilis.

In this study, the natural intracellular β-galactosidase (lacZBa) from Bacillus aryabhattai was expressed extracellularly in Bacillus subtilis. Sec and Tat signal peptides from different secretion pathways were incorporated to facilitate extracellular secretion of lacZBa, resulting in a yield of only 0.54 U/mL.

In-situ CBM3-modified bacterial cellulose film with improved mechanical properties.

Cellulose materials have poor wet strength and are susceptible to acidic or basic environments. Herein, we developed a facile strategy to modify bacterial cellulose (BC) with a genetically engineered Family 3 Carbohydrate-Binding Module (CBM3). To assess the effect of BC films, water adsorption rate (WAR), water holding capacity (WHC), water contact angle (WCA), and mechanical and barrier properties were determined.

A High-Specific-Activity L-aspartate-α-Decarboxylase from Bacillus aryabhattai Gel-09 and Site-Directed Mutation to Improve Its Substrate Tolerance.

L-aspartate-α-decarboxylase (ADC) can recognize L-aspartic acid specifically and catalyze the decarboxylation of L-aspartic acid to β-alanine. In this study, a novel L-aspartate-α-decarboxylase (BaADC) with high specific activity from Bacillus aryabhattai Gel-09 was heterologously expressed and characterized. It exhibited optimal enzyme activity at pH 5.

[Advances in heterologous expression, structural elucidation and molecular modification of pullulanase].

Starch is composed of glucose units linked by α-1, 4-glucoside bond and α-1, 6-glucoside bond. It is the main component of foods and the primary raw material for starch processing industry. Pullulanase can effectively hydrolyze the α-1, 6-glucoside bond in starch molecules.

Toxicity and inhibition mechanism of gallic acid on physiology and fermentation performance of Escherichia coli.

Gallic acid is a natural phenolic acid that has a stress inhibition effect on Escherichia coli. This study by integrates fermentation characteristics and transcriptional analyses to elucidate the physiological mechanism of E. coli 3110 response to gallic acid.

A Novel Thermal-Activated β-Galactosidase from GEL-09 for Lactose Hydrolysis in Milk.

β-Galactosidase has been greatly used in the dairy industry. This study investigated a novel thermostable β-galactosidase (lacZBa) from GEL-09 and evaluated the hydrolytic performance of this enzyme. Firstly, the lacZBa-encoding gene was cloned and overexpressed in BL21(DE3).

Expression, biochemical and structural characterization of high-specific-activity β-amylase from Bacillus aryabhattai GEL-09 for application in starch hydrolysis.

Background: β-amylase (EC 3.2.1.

Applied evolution: Dual dynamic regulations-based approaches in engineering intracellular malonyl-CoA availability.

Malonyl-CoA is an important building block for microbial synthesis of numerous pharmaceutically interesting or fatty acid-derived compounds including polyketides, flavonoids, phenylpropanoids and fatty acids. However, the tightly regulated intracellular malonyl-CoA availability often impedes overall product formation. Here, in order to unleash this tightly cellular behavior, we present evolution: dual dynamic regulations-based approaches to write artificial robust and dynamic function into intricate cellular background.

Developing a pathway-independent and full-autonomous global resource allocation strategy to dynamically switching phenotypic states.

A grand challenge of biological chemical production is the competition between synthetic circuits and host genes for limited cellular resources. Quorum sensing (QS)-based dynamic pathway regulations provide a pathway-independent way to rebalance metabolic flux over the course of the fermentation. Most cases, however, these pathway-independent strategies only have capacity for a single QS circuit functional in one cell.

Highly sensitive detection of lipopolysaccharide based on collaborative amplification of dual enzymes.

In this work, a novel electrochemical biosensor is developed for facile and highly sensitive detection of lipopolysaccharide (LPS) based on collaboration of dual enzymes for multiple-stages signal amplification. Through ingenious design, the specific recognition of target LPS is transformed to the exonuclease III (Exo III)-assisted interface DNA cycling collaborated with the terminal deoxynucleotidyl transferase (TdT)-catalyzed DNA extension, finally inducing significant electrochemical signal concerned with the concentration of LPS. This paper mainly discusses the detection principle, optimization of key factors, and the analytical performance of the biosensor.

Synthesis of Isorhamnetin-3--Rhamnoside by a Three-Enzyme (Rhamnosyltransferase, Glycine Max Sucrose Synthase, UDP-Rhamnose Synthase) Cascade Using a UDP-Rhamnose Regeneration System.

Isorhamnetin-3--rhamnoside was synthesized by a highly efficient three-enzyme (rhamnosyltransferase, glycine max sucrose synthase and uridine diphosphate (UDP)-rhamnose synthase) cascade using a UDP-rhamnose regeneration system. The rhamnosyltransferase gene (78D1) from was cloned, expressed, and characterized in . The optimal activity was at pH 7.

Mitigation of environmental pollution by genetically engineered bacteria - Current challenges and future perspectives.

Industries are the paramount driving force for the economic and technological development of society. However, the flourishing industrialization and unimpeded growth of current production unit's result in widespread environmental pollution due to increased discharge of wastes loaded with baleful, hazardous, and carcinogenic contaminants. Physicochemical-based remediation means are costly, create a secondary disposal problem and remain inadequate for pollution mitigating because of the continuous emergence of new recalcitrant pollutants.

Efficient production of aggregation prone 4-α-glucanotransferase by combined use of molecular chaperones and chemical chaperones in Escherichia coli.

In this study, a combined optimization strategy, based on co-expression of molecular chaperones and supplementation of osmolytes, was used to reduce the formation of inclusion bodies and enhance the expression of the soluble form of 4-α-glucanotransferase. The 4-α-glucanotransferase yield was enhanced by co-expression with pGro7 and supplementation of trimetlylamine oxide. Subsequently, the effects of process conditions (temperature, inducer concentration, and arabinose concentration) on cell growth and 4-α-glucanotransferase production were also investigated in shake flasks.

Construction of artificial micro-aerobic metabolism for energy- and carbon-efficient synthesis of medium chain fatty acids in Escherichia coli.

Medium-chain (C-C) chemicals are important components of fuels, commodities and fine chemicals. Numerous exciting achievements have proven reversed β-oxidation cycle as a promising platform to synthesize these chemicals. However, under native central carbon metabolism, energetic and redox constraints limit the efficient operation of reversed β-oxidation cycle.

Production of recombinant beta-amylase of Bacillus aryabhattai.

In this study, the effects of carbon source, nitrogen source, and metal ions on cell growth and Bacillus aryabhattai β-amylase production in recombinant Brevibacillus choshinensis were investigated. The optimal medium for β-amylase production, containing glucose (7.5 g·L), pig bone peptone (40.

Sensitive detection of chloramphenicol based on Ag-DNAzyme-mediated signal amplification modulated by DNA/metal ion interaction.

We here report a novel method for antibiotic detection by making use of DNA/metal ion interaction coupled with Ag-DNAzyme cleavage-mediated signal amplification. Taking the analysis of chloramphenicol (CAP) as an example, upon the specific recognition between the antibiotic CAP and its aptamer, the secondary structure of the DNA aptamer shaped by C-Ag-C base mismatches will be altered, liberating the pre-captured Ag. Subsequently, the free Ag provided as a cofactor can activate the Ag-DNAzyme, which behaves recycled cleavage of substrate DNA on the electrode surface for signal amplification.

Efficient Expression of Maltohexaose-Forming -Amylase from in SP3 and Its Use in Maltose Production.

The maltohexaose-forming, Ca-independent -amylase gene from (AmyMH) was efficiently expressed in SP3. To improve the production of AmyMH in SP3, the temperature and initial pH of culture medium were optimized. In addition, single-factor and response surface methodologies were pursued to optimize culture medium.

Improving the reversibility of thermal denaturation and catalytic efficiency of Bacillus licheniformis α-amylase through stabilizing a long loop in domain B.

The reversibility of thermal denaturation and catalytic efficiency of Bacillus licheniformis α-amylase were improved through site-directed mutagenesis. By using multiple sequence alignment and PoPMuSiC algorithm, Ser187 and Asn188, which located within a long loop in Domain B of Bacillus licheniformis α-amylase, were selected for mutation. In addition, Ala269, which is adjacent to Ser187 and Asn188, was also investigated.

High-level extracellular protein production in Bacillus subtilis using an optimized dual-promoter expression system.

Background: We recently constructed a Bacillus subtilis strain (CCTCC M 2016536) from which we had deleted the srfC, spoIIAC, nprE, aprE and amyE genes. This strain is capable of robust recombinant protein production and amenable to high-cell-density fermentation. Because the promoter is among the factors that influence the production of target proteins, optimization of the initial promoter, P from Bacillus amyloliquefaciens, should improve protein expression using this strain.

L-Tryptophan Production in Escherichia coli Improved by Weakening the Pta-AckA Pathway.

Acetate accumulation during the fermentation process of Escherichia coli FB-04, an L-tryptophan production strain, is detrimental to L-tryptophan production. In an initial attempt to reduce acetate formation, the phosphate acetyltransferase gene (pta) from E. coli FB-04 was deleted, forming strain FB-04(Δpta).