Pathway and protein channel engineering of for improved production of desthiobiotin and biotin.

Biotin (vitamin B) is a crucial cofactor for various metabolic processes and has significant applications in pharmaceuticals, cosmetics, and animal feed. , a well-studied Gram-positive bacterium, presents a promising host for biotin production due to its Generally Recognized as Safe (GRAS) status, robust genetic tractability, and capacity for metabolite secretion. This study focuses on the metabolic engineering of .

Highly flexible cell membranes are the key to efficient production of lipophilic compounds.

Lipophilic compounds have a variety of positive effects on human physiological functions and exhibit good effects in the prevention and treatment of clinical diseases. This has led to significant interest in the technical applications of synthetic biology for the production of lipophilic compounds. However, the strict selective permeability of the cell membrane and the hydrophobic nature of lipophilic compounds pose significant challenges to their production.

A hybrid RNA-protein biosensor for high-throughput screening of adenosylcobalamin biosynthesis.

Genetically encoded circuits have been successfully utilized to assess and characterize target variants with desirable traits from large mutant libraries. Adenosylcobalamin is an essential coenzyme that is required in many intracellular physiological reactions and is widely used in the pharmaceutical and food industries. High-throughput screening techniques capable of detecting adenosylcobalamin productivity and selecting superior adenosylcobalamin biosynthesis strains are critical for the creation of an effective microbial cell factory for the production of adenosylcobalamin at an industrial level.

Multivariate modular metabolic engineering and medium optimization for vitamin B production by .

Vitamin B is a complex compound synthesized by microorganisms. The industrial production of vitamin B relies on specific microbial fermentation processes. has been utilized as a host for the biosynthesis of vitamin B, incorporating approximately 30 heterologous genes.

An Efficient CRISPR/Cas12e System for Genome Editing in .

CRISPR/Cas systems have been widely used in the precise and traceless genetic engineering of bacteria. 320 (SM320) is a Gram-negative bacterium with a low efficiency of homologous recombination but a strong ability to produce vitamin B. Here, a CRISPR/Cas12e-based genome engineering toolkit, CRISPR/Cas12eGET, was constructed in SM320.

CRISPR/Cas tools for enhancing the biopreservation ability of lactic acid bacteria in aquatic products.

Lactic acid bacteria (LAB) plays a crucial role in aquatic products biopreservation as it can inhibit many bacteria, in particular the specific spoilage organisms (SSOs) of aquatic products, by competing for nutrients or producing one or more metabolites which have antimicrobial activity, such as bacteriocins. spp. and spp.

Promoting Sexuality Education for Children and Adolescents on a Large Scale: Program Design, Organizational Cooperation Network and Administrative Mobilization.

In China, the promotion of sexuality education for children and adolescents is hindered by a relatively conservative culture and insufficient drive from the government. With the government and the market failing to deliver in this area, social organizations, such as the third sector, are playing an important role. This paper mainly discusses how Chinese social organizations promote sexuality education for children and adolescents on a large scale.

A versatile Cas12k-based genetic engineering toolkit (C12KGET) for metabolic engineering in genetic manipulation-deprived strains.

The genetic modification of microorganisms is conducive to the selection of high-yield producers of high-value-added chemicals, but a lack of genetic tools hinders the industrialization of most wild species. Therefore, it is crucial to develop host-independent gene editing tools that can be used for genetic manipulation-deprived strains. The Tn7-like transposon from Scytonema hofmanni has been shown to mediate homologous recombination-independent genomic integration after heterologous expression in Escherichia coli, but the integration efficiency of heterologous sequences larger than 5 kb remains suboptimal.

Application of Biotechnology in Specific Spoilage Organisms of Aquatic Products.

Aquatic products are delicious and have high nutritive value, however, they are highly perishable during storage due to the growth and metabolism of microorganisms. The spoilage process of aquatic products was demonstrated to be highly related to the composition of microorganisms, in which the specific spoilage organisms (SSOs) are the main factors. In this article, the spoilage indicators of SSOs were systematically described, which could make a comprehensive evaluation of the quality of aquatic products.

CRISPR/Cas Technologies and Their Applications in .

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems have revolutionized genome editing and greatly promoted the development of biotechnology. However, these systems unfortunately have not been developed and applied in bacteria as extensively as in eukaryotic organism. Here, the research progress on the most widely used CRISPR/Cas tools and their applications in is summarized.

Establishment of a Biosensor-based High-Throughput Screening Platform for Tryptophan Overproduction.

With the flexibility to fold into complex structures, RNA is well-suited to act as a cellular sensor to recognize environmental fluctuations and respond to changes by regulating the corresponding genes. In this study, we established a high-throughput screening platform to screen tryptophan high-producing strains from a large repertoire of candidate strains. This platform consists of a tryptophan-specific aptamer-based biosensor and fluorescence-activated droplet sorting technology.

Application of different types of CRISPR/Cas-based systems in bacteria.

As important genome editing tools, CRISPR/Cas systems, especially those based on type II Cas9 and type V Cas12a, are widely used in genetic and metabolic engineering of bacteria. However, the intrinsic toxicity of Cas9 and Cas12a-mediated CRISPR/Cas tools can lead to cell death in some strains, which led to the development of endogenous type I and III CRISPR/Cas systems. However, these systems are hindered by complicated development and limited applications.

Identification of a xylose-inducible promoter and its application for improving vitamin B production in Sinorhizobium meliloti.

Sinorhizobium meliloti 320 is a vitamin B (VB ) high-producing strain that has been isolated and identified in our previous study. Because the regulatory toolbox for S. meliloti is limited, we searched for new genetic components and identified the two xylose-inducible promoters P and P based on a promoter-probe vector with a green fluorescent protein (GFP) as reporter.

Optimization of hydrogenobyrinic acid biosynthesis in Escherichia coli using multi-level metabolic engineering strategies.

Background: Hydrogenobyrinic acid is a key intermediate of the de-novo aerobic biosynthesis pathway of vitamin B. The introduction of a heterologous de novo vitamin B biosynthesis pathway in Escherichia coli offers an alternative approach for its production. Although E.

Enhanced production of d-psicose 3-epimerase in Bacillus subtilis by regulation of segmented fermentation.

d-Psicose 3-epimerase is an enzyme that catalyzes the synthesis of d-psicose from d-fructose. We cloned the d-psicose 3-epimerase from Ruminococcus sp. (RDPE) and expressed it in Bacillus subtilis A311.

Strategies for Applying Nonhomologous End Joining-Mediated Genome Editing in Prokaryotes.

The emergence of genome editing technology based on the CRISPR/Cas system enabled revolutionary progress in genetic engineering. Double-strand breaks (DSBs), which can be induced by the CRISPR/Cas9 system, cause serious DNA damage that can be repaired by a homologous recombination (HR) system or the nonhomologous end joining (NHEJ) pathway. However, many bacterial species have a very weak HR system.

Engineering a vitamin B high-throughput screening system by riboswitch sensor in Sinorhizobium meliloti.

Background: As a very important coenzyme in the cell metabolism, Vitamin B (cobalamin, VB) has been widely used in food and medicine fields. The complete biosynthesis of VB requires approximately 30 genes, but overexpression of these genes did not result in expected increase of VB production. High-yield VB-producing strains are usually obtained by mutagenesis treatments, thus developing an efficient screening approach is urgently needed.

[Purification and characterization of S-adenosyl-L-methionine:uroporphyrinogen Ⅲ methyltransferase from Rhodobacter capsulatus SB1003].

Biosynthesis of vitamin B₁₂ (VB₁₂) requires the methylation at positions C-2 and C-7 of the precursor uroporphyrinogen Ⅲ (urogen Ⅲ) to precorrin-2 by S-adenosyl-L-methionine uroporphyrinogen Ⅲ methyltransferase (SUMT), which is a potential bottleneck step. Most of SUMTs are inhibited by urogen Ⅲ and by-product S-adenosyl-L-homocysteine (SAH). In order to mine an SUMT that lacks such an inhibitory property to drive greater flux through the VB₁₂ biosynthetic pathway, we cloned two SUMT genes (RCcobA1, RCcobA2) from Rhodobacter capsulatus SB1003 and expressed them in Escherichia coli BL21 (DE3).

High-Efficiency Secretion of β-Mannanase in Bacillus subtilis through Protein Synthesis and Secretion Optimization.

The manno endo-1,4-mannosidase (β-mannanase, EC. 3.2.

High-Yield Preparation and Electrochemical Properties of Few-Layer MoS2 Nanosheets by Exfoliating Natural Molybdenite Powders Directly via a Coupled Ultrasonication-Milling Process.

Cost-effective and scalable preparation of two-dimensional (2D) molybdenum disulfide (MoS2) has been the bottleneck that limits their applications. This paper reports a novel coupled ultrasonication-milling (CUM) process to exfoliate natural molybdenite powders to achieve few-layer MoS2 (FL-MoS2) nanosheets in the solvent of N-methyl-2-pyrrolidone (NMP) with polyvinylpyrrolidone (PVP) molecules. The synergistic effect of ultrasonication and sand milling highly enhanced the exfoliation efficiency, and the precursor of natural molybdenite powders minimizes the synthetic cost of FL-MoS2 nanosheets.

A newly isolated and identified vitamin B12 producing strain: Sinorhizobium meliloti 320.

Vitamin B12 (Cobalamin, VB12) has several physiological functions and is widely used in pharmaceutical and food industries. A new unicellular species was extracted from China farmland, and the strain could produce VB12 which was identified by HPLC and HPLC-MS/MS. 16S rDNA analysis reveals this strain belongs to the species Sinorhizobium meliloti and we named it S.

In Vitro Optimization of Enzymes Involved in Precorrin-2 Synthesis Using Response Surface Methodology.

In order to maximize the production of biologically-derived chemicals, kinetic analyses are first necessary for predicting the role of enzyme components and coordinating enzymes in the same reaction system. Precorrin-2 is a key precursor of cobalamin and siroheme synthesis. In this study, we sought to optimize the concentrations of several molecules involved in precorrin-2 synthesis in vitro: porphobilinogen synthase (PBGS), porphobilinogen deaminase (PBGD), uroporphyrinogen III synthase (UROS), and S-adenosyl-l-methionine-dependent urogen III methyltransferase (SUMT).

An enzymatic assay for high-throughput screening of cytidine-producing microbial strains.

Cytidine is an industrially useful precursor for the production of antiviral compounds and a variety of industrial compounds. Interest in the microbial production of cytidine has grown recently and high-throughput screening of cytidine over-producers is an important approach in large-scale industrial production using microorganisms. An enzymatic assay for cytidine was developed combining cytidine deaminase (CDA) and indophenol method.