Engineering Glucosamine-6-Phosphate Synthase to Achieve Efficient One-Step Biosynthesis of Glucosamine.

As an important functional monosaccharide, glucosamine (GlcN) is widely used in fields such as medicine, food nutrition, and health care. Here, we report a distinct GlcN biosynthesis method that utilizes engineered glucosamine-6-phosphate synthase (GlmS) to convert D-fructose to directly generate GlcN. The best variant obtained by using a combinatorial active-site saturation test/iterative saturation mutagenesis (CAST/ISM) strategy was a quadruple mutant S596D/V597G/S347H/G299Q (GlmS-BK19), which has a catalytic activity 1736-fold that of the wild type toward D-fructose.

Pigment production by a newly isolated strain SYBC-L7 in solid-state fermentation.

Natural pigments are playing important roles in our daily lives. They not only make products colorful but also provide various health benefits for humans. In addition, genus, listed as food- and cosmetic-grade microorganism, is one of the promising organisms for developing natural pigments.

Improving the decolorization activity of Bacillus pumilus W3 CotA-laccase to Congo Red by rational modification.

Congo Red (CR) is a typical azo dye with highly toxic and carcinogenic properties. This study aimed to improve the decolorization activity of Bacillus pumilus W3 CotA-laccase for azo dye CR. This work analyzed the interaction between CotA-laccase and CR based on homology modeling and molecular docking.

Enhancing the decolorization activity of Bacillus pumilus W3 CotA-laccase to Reactive Black 5 by site-saturation mutagenesis.

Reactive Black 5 (RB5) is a typical refractory azo dye. Widespread utilization of RB5 has caused a variety of environmental and health problems. The enzymatic degradation of RB5 can be a promising solution due to its superiority as an eco-friendly and cost-competitive process.

Recombinant Horseradish Peroxidase C1A Immobilized on Hydrogel Matrix for Dye Decolorization and Its Mechanism on Acid Blue 129 Decolorization.

In this study, horseradish peroxidase C1A (HRP C1A) from Armoracia rusticana was expressed in Escherichia coli as an inclusion body. Subsequently, an active recombinant HRP C1A was obtained by refolding gradually using dilution-ultrafiltration. The recombinant HRP C1A was immobilized on agarose-chitosan hydrogel at 86.

Extracellular expression of mutant CotA-laccase SF in Escherichia coli and its degradation of malachite green.

In this study, mutant CotA-laccase SF was successfully expressed in Escherichia coli by co-expression with phospholipase C. The optimized extracellular expression of CotA-laccase SF was 1257.22 U/L.

Enhancement in catalytic activity of CotA-laccase from Bacillus pumilus W3 via site-directed mutagenesis.

CotA-laccases are potential enzymes that are widely used in decolorization of dyes and degradation of toxic substances. In this study, a novel CotA-laccase gene from Bacillus pumilus W3 was applied for rational design. After a series of site-directed genetic mutations, the mutant S208G/F227A showed a 5.

Bacterial laccases: promising biological green tools for industrial applications.

Multicopper oxidases (MCOs) are a pervasive family of enzymes that oxidize a wide range of phenolic and nonphenolic aromatic substrates, concomitantly with the reduction of dioxygen to water. MCOs are usually divided into two functional classes: metalloxidases and laccases. Given their broad substrate specificity and eco-friendliness (molecular oxygen from air as is used as the final electron acceptor and they only release water as byproduct), laccases are regarded as promising biological green tools for an array of applications.

Functional expression enhancement of Bacillus pumilus CotA-laccase mutant WLF through site-directed mutagenesis.

Bacterial laccases are potential enzymes for biotechnological applications, such as detoxification of industrial effluents, decolorization of textile, and dimerization of phenolic acids, due to their remarkable advantages, including broad substrate spectrum, high thermostability, wide pH scope, and tolerance to alkaline environments. L386W/G417L/G57F (abbreviated as WLF), a good mutant of CotA-laccase from Bacillus pumilus W3, has been constructed and reported by our laboratory with highly improved catalytic efficiency. However, the low-functional expression level of mutant WLF in Escherichia coli was a shortcoming.

Establishment of a markerless multiple-gene deletion method based on Cre/loxP mutant system for Bacillus pumilus.

In this study, we established a Cre/loxP mutant recombination system (Cre/lox71-66 system) for markerless gene deletion to facilitate our follow-up rational genetic engineering to the strain Bacillus pumilus W3. This modified method uses two mutant loxP sites, which after recombination creates a double-mutant loxP site that is poorly recognized by Cre recombinase, facilitating multiple gene deletions in a single genetic background. Two selected genes, cotA and sigF, were continuously knocked out and verified at different levels using this method.

Production of spore laccase from Bacillus pumilus W3 and its application in dye decolorization after immobilization.

Given that spore laccase from the Bacillus genus is heat- and alkali-resistant, it is more suitable for industrial applications than fungal laccase. To determine the optimal culture conditions for spore laccase production, the effects of Cu concentration, oxygen content, and culture time on spore laccase production from Bacillus pumilus W3 were investigated. The optimal production parameters were 0.

Improving the catalytic efficiency of Bacillus pumilus CotA-laccase by site-directed mutagenesis.

Bacterial laccases are potential enzymes for biotechnological applications because of their remarkable advantages, such as broad substrate spectrum, various reactions, high thermostability, wide pH range, and resistance to strongly alkaline environments. However, the use of bacterial laccases for industrialized applications is limited because of their low expression level and catalytic efficiency. In this study, CotA, a bacterial laccase from Bacillus pumilus, was engineered through presumptive reasoning and rational design approaches to overcome low catalytic efficiency and thermostability.

Complete genome sequence of Bacillus pumilus W3: A strain exhibiting high laccase activity.

Here we report the full genome sequence of Bacillus pumilus W3, which was isolated from raw gallnut honey in Nandan County, Guangxi Province of China, showing high CotA-laccase activity. The W3 strain contains 3,745,123bp with GC content of 41.39%, and contains 3695 protein-coding genes, 21 rRNAs and 70 tRNAs.

Stimulating the biosynthesis of antroquinonol by addition of effectors and soybean oil in submerged fermentation of Antrodia camphorata.

Antrodia camphorata is a precious medicinal mushroom that has attracted increasing attentions. Antroquinonol has been considered as being among the most biologically active components of A. camphorata.

Molecular cloning, characterization, and dye-decolorizing ability of a temperature- and pH-stable laccase from Bacillus subtilis X1.

Laccases from fungal origin are typically unstable at high temperatures and alkaline conditions. This characteristic limits their practical applications. In this study, a new bacterial strain exhibiting laccase activity was isolated from raw fennel honey samples and identified as Bacillus subtilis X1.

[Antimicrobial effects of qingkailing injection extract and combination therapy of qingkailing injection and antibiotics on bacteria carrying blaNDM-1 resistance gene].

Objective: To research the bacteriostatic effects of Qingkailing Injection Extract (QKLIE) and combination therapy of Qingkailing Injection (QKLI) and antibiotics on bacteria carrying New Delhi metallo-3-lactamase 1 (NDM-1) blaNDM-1 resistance gene, and to determine their minimal inhibitory concentrations (MIC).

Methods: The antimicrobial experiments of QKLIE (Radix Isatidis, baicalin, gardenia, honeysuckle) and combination therapy of QKLI and antibiotics were performed by using the agar dilution method and K-B method. The MIC was determined from each extract.

Production, characterization, cloning and sequence analysis of a monofunctional catalase from Serratia marcescens SYBC08.

A monofunctional catalase from Serratia marcescens SYBC08 produced by liquid state fermentation in 7 liter fermenter was isolated and purified by ammonium sulfate precipitation (ASP), ion exchange chromatography (IEC), and gel filtration (GF) and characterized. Its sequence was analyzed by LC-MS/MS technique and gene cloning. The highest catalase production (20,289 U · ml(-1)) was achieved after incubation for 40 h.

Isolation and identification of a new hypocrellin A-producing strain Shiraia sp. SUPER-H168.

A new hypocrellin A-producing strain, Shiraia sp. SUPER-H168, was isolated from tissues of bamboo, Brachystachyum densiflorum. The morphology of this strain was characterized with a light microscope and a scanning electronic microscope.