Construction of antibiotic-free riboflavin producer in by metabolic engineering strategies with a plasmid stabilization system.

Riboflavin, an important vitamin utilized in pharmaceutical products and as a feed additive, is mainly produced by metabolically engineered bacterial fermentation. However, the reliance on antibiotics in the production process leads to increased costs and safety risks. To address these challenges, an antibiotic-free riboflavin producer was constructed using metabolic engineering approaches coupled with a novel plasmid stabilization system.

Application of modern synthetic biology technology in aromatic amino acids and derived compounds biosynthesis.

Aromatic amino acids (AAA) and derived compounds have enormous commercial value with extensive applications in the food, chemical and pharmaceutical fields. Microbial production of AAA and derived compounds is a promising prospect for its environmental friendliness and sustainability. However, low yield and production efficiency remain major challenges for realizing industrial production.

Utilizing 5' UTR Engineering Enables Fine-Tuning of Multiple Genes within Operons to Balance Metabolic Flux in .

The application of synthetic biology tools to modulate gene expression to increase yield has been thoroughly demonstrated as an effective and convenient approach in industrial production. In this study, we employed a high-throughput screening strategy to identify a 5' UTR sequence from the genome of 168. This sequence resulted in a 5.

Microbial production of branched chain amino acids: Advances and perspectives.

Branched-chain amino acids (BCAAs) such as L-valine, L-leucine, and L-isoleucine are widely used in food and feed. To comply with sustainable development goals, commercial production of BCAAs has been completely replaced with microbial fermentation. However, the efficient production of BCAAs by microorganisms remains a serious challenge due to their staggered metabolic networks and cell growth.

Supramolecular crystals of Mn(15-crown-5)(MnCl)(DMF) with dielectric phase transition, high quantum yield and phase transition-induced luminescence enhancement behavior.

The supramolecular crystals, Mn(15-crown-5)(MnCl)(DMF), (1; 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane), were synthesized a self-assembly strategy under ambient conditions. Comprehensive characterization of the crystals involved microanalysis for C, H, and N elements, thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) and single-crystal X-ray diffraction techniques. The results reveal that 1 undergoes a two-step thermotropic and isostructural phase transition at around 217 K and 351 K upon heating.

Combining protein and metabolic engineering strategies for high-level production of L-theanine in Corynebacterium glutamicum.

L-theanine is a natural non-protein amino acid with wide applications. Thus, a high yield of L-theanine production is required on an industrial scale. Herein, an efficient L-theanine-producing strain of Corynebacterium glutamicum was constructed by combining protein and metabolic engineering.

Engineering serine hydroxymethyltransferases for efficient synthesis of L-serine in Escherichia coli.

L-serine is a high-value amino acid widely used in the food, medicine, and cosmetic industries. However, the low yield of L-serine has limited its industrial production. In this study, a cellular factory for efficient synthesis of L-serine was obtained by engineering the serine hydroxymethyltransferases (SHMT).

Systematic metabolic engineering of Yarrowia lipolytica for the enhanced production of erythritol.

In recent times, there has been a growing interest in exploring microbial strains that exhibit enhanced erythritol productivity. Nonetheless, the lack of advanced synthetic biology tools has limited rapid strain development. In this study, the CRISPR/Cas9 system was employed to genetically modify Yarrowia lipolytica at the chromosomal level, which could improve the production of erythritol while saving the time required to markers recovery, and realizing the rapid construction of high-erythritol strains.

Construction of a plasmid-free L-leucine overproducing Escherichia coli strain through reprogramming of the metabolic flux.

Background: L-Leucine is a high-value amino acid with promising applications in the medicine and feed industries. However, the complex metabolic network and intracellular redox imbalance in fermentative microbes limit their efficient biosynthesis of L-leucine.

Results: In this study, we applied rational metabolic engineering and a dynamic regulation strategy to construct a plasmid-free, non-auxotrophic Escherichia coli strain that overproduces L-leucine.

Combinatorial protein engineering and transporter engineering for efficient synthesis of L-Carnosine in Escherichia coli.

L-Carnosine has various physiological functions and is widely used in cosmetics, medicine, food additives, and other fields. However, the yield of L-Carnosine obtained by biological methods is far from the level of industrial production. Herein, a cell factory for efficient synthesis of L-Carnosine was constructed based on transporter engineering and protein engineering.

Multidimensional engineering of Escherichia coli for efficient synthesis of L-tryptophan.

Development of microbial cell factory for L-tryptophan (L-trp) production has received widespread attention but still requires extensive efforts due to weak metabolic flux distribution and low yield. Here, the riboswitch-based high-throughput screening (HTS) platform was established to construct a powerful L-trp-producing chassis cell. To facilitate L-trp biosynthesis, gene expression was regulated by promoter and N-terminal coding sequences (NCS) engineering.

Organic-inorganic haloargentate hybrids of [Me-dabco]AgX (X = I or Br) with halide ions manipulating the crystal structure, phase transition, and dielectric behavior.

Two haloargentate hybrids, [Me-dabco]AgX (Me-dabco = 1-methyl-1,4-diazabicyclo-[2.2.2]octan-1-ium, X = I (1) or Br (2)), with the same formula but different structures have been synthesized by a slow evaporation method and characterized by microanalysis, infrared spectroscopy, thermogravimetric, and powder X-ray diffraction techniques.

Phase transition and ionic conduction enhancement induced by co-doping of LiI and MnI in a one-dimensional lead iodide perovskite.

Herein, we demonstrated the unique advantage of a mechanochemical reaction to prepare a salt with hard and soft acid and base ions concurrently by solution synthesis owing to the soft acid preferring to combine with the soft base and . We prepared BuNLiMnPbI ( = 0.011-0.

N20D/N116E Combined Mutant Downward Shifted the pH Optimum of NADH Oxidase.

Cofactor regeneration is indispensable to avoid the addition of large quantities of cofactor NADH or NAD in oxidation-reduction reactions. Water-forming NADH oxidase (Nox) has attracted substantive attention as it can oxidize cytosolic NADH to NAD without concomitant accumulation of by-products. However, its applications have some limitations in some oxidation-reduction processes when its optimum pH is different from its coupled enzymes.

A {CuI} chain hybrid with two-step phase transition, switchable dielectrics, thermochromism and piezochromism.

Stimuli-responsive smart materials have applications in a range of technologies. Herein, we present a hybrid (1), built from MeEtN organic cations and {CuI} inorganic chains with Cu⋯Cu metal⋯metal interactions. The two-step phase transition undergone in 1 on the first heating and the phase transition at a lower temperature show symmetry-broken features, leading to switchable dielectrics; the one at a higher temperature displays isomorphic characteristics.

Direct evolution of riboflavin kinase significantly enhance flavin mononucleotide synthesis by design and optimization of flavin mononucleotide riboswitch.

Flavin mononucleotide (FMN) is the active form of riboflavin. It has a wide range of application scenarios in the pharmaceutical and food additives. However, there are limitations in selecting generic high-throughput screening platforms that improve the properties of enzymes.

Efficient Whole-Cell Biotransformation for α-Arbutin Production through the Engineering of Sucrose Phosphorylase Combined with Engineered Cell Modification.

α-Arbutin is extensively used in cosmetic industries. The lack of highly active enzymes and the cytotoxicity of hydroquinone limit the biosynthesis of α-arbutin. In this study, a whole-cell biocatalytic approach based on enzyme engineering and engineered cell modification was identified as effective in enhancing α-arbutin production.

A Novel Method to Screen Strong Constitutive Promoters in and for Industrial Applications.

Promoters serve as the switch of gene transcription, playing an important role in regulating gene expression and metabolites production. However, the approach to screening strong constitutive promoters in microorganisms is still limited. In this study, a novel method was designed to identify strong constitutive promoters in and based on random genomic interruption and fluorescence-activated cell sorting (FACS) technology.

Efficient biosynthesis of (R)-mandelic acid from styrene oxide by an adaptive evolutionary Gluconobacter oxydans STA.

Background: (R)-mandelic acid (R-MA) is a highly valuable hydroxyl acid in the pharmaceutical industry. However, biosynthesis of optically pure R-MA remains significant challenges, including the lack of suitable catalysts and high toxicity to host strains. Adaptive laboratory evolution (ALE) was a promising and powerful strategy to obtain specially evolved strains.

Enhancing erythritol production from crude glycerol in a wild-type by metabolic engineering.

Erythritol is a zero-calorie sweetener that is widely used in the food, pharmaceutical, and medical industries. Crude glycerol is the main by-product of biodiesel, and the effective utilization of crude glycerol will help to improve biodiesel viability. Previous studies on the production of erythritol from using crude glycerol as a carbon source have focused on optimizing the fermentation process of the mutant Wratislavia K1, while metabolic engineering has not been successfully applied.

Acetoin production from lignocellulosic biomass hydrolysates with a modular metabolic engineering system in Bacillus subtilis.

Background: Acetoin (AC) is a vital platform chemical widely used in food, pharmaceutical and chemical industries. With increasing concern over non-renewable resources and environmental issues, using low-cost biomass for acetoin production by microbial fermentation is undoubtedly a promising strategy.

Results: This work reduces the disadvantages of Bacillus subtilis during fermentation by regulating genes involved in spore formation and autolysis.

Improving prodigiosin production by transcription factor engineering and promoter engineering in .

Prodigiosin (PG), a red linear tripyrrole pigment produced by , has attracted attention due to its immunosuppressive, antimicrobial, and anticancer properties. Although many studies have been used to dissect the biosynthetic pathways and regulatory network of prodigiosin production in , few studies have been focused on improving prodigiosin production through metabolic engineering in this strain. In this study, transcription factor engineering and promoter engineering was used to promote the production of prodigiosin in JNB5-1.

[Efficient biosynthesis of -mannitol by coordinated expression of a two-enzyme cascade].

-mannitol is widely used in the pharmaceutical and medical industries as an important precursor of antitumor drugs and immune stimulants. However, the cost of the current enzymatic process for -mannitol synthesis is high, thus not suitable for commercialization. To address this issue, an efficient mannitol dehydrogenase GDH used for the conversion and a glucose dehydrogenase GDH used for NADH regeneration were screened, respectively.