CRISPR-Cas9 mediated engineering of Bacillus licheniformis for industrial production of (2R,3S)-butanediol.

Bacillus lichenformis is an industrially promising generally recognized as safe (GRAS) strain that can be used for the production of a valuable chemical, 2,3-butanediol (BDO). Conventional gene deletion vectors and/or methods are time-consuming and have poor efficiency. Therefore, clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 mediated homologous recombination was used to engineer a newly isolated and UV-mutagenized B.

Engineering a newly isolated Bacillus licheniformis strain for the production of (2R,3R)-butanediol.

Several microorganisms can produce 2,3-butanediol (BDO), an industrially promising chemical. In this study, a Bacillus licheniformis named as 4071, was isolated from soil sample. It is a GRAS (generally recognized as safe) strain and could over-produce 2,3-BDO.

Isolation and Evaluation of Strains for Industrial Production of 2,3-Butanediol.

Biologically produced 2,3-butanediol (2,3-BDO) has diverse industrial applications. In this study, schematic isolation and screening procedures were designed to obtain generally regarded as safe (GRAS) and efficient 2,3-BDO producers. Over 4,000 candidate strains were isolated by pretreatment and enrichment, and the isolated strains were further screened by morphological, biochemical, and genomic analyses.

Metabolic engineering of Klebsiella pneumoniae based on in silico analysis and its pilot-scale application for 1,3-propanediol and 2,3-butanediol co-production.

Klebsiella pneumoniae naturally produces relatively large amounts of 1,3-propanediol (1,3-PD) and 2,3-butanediol (2,3-BD) along with various byproducts using glycerol as a carbon source. The ldhA and mdh genes in K. pneumoniae were deleted based on its in silico gene knockout simulation with the criteria of maximizing 1,3-PD and 2,3-BD production and minimizing byproducts formation and cell growth retardation.

Effects of mutation of 2,3-butanediol formation pathway on glycerol metabolism and 1,3-propanediol production by Klebsiella pneumoniae J2B.

The current study investigates the impact of mutation of 2,3-butanediol (BDO) formation pathway on glycerol metabolism and 1,3-propanediol (PDO) production by lactate dehydrogenase deficient mutant of Klebsiella pneumoniae J2B. To this end, BDO pathway genes, budA, budB, budC and budO (whole-bud operon), were deleted from K. pneumoniae J2B ΔldhA and the mutants were studied for glycerol metabolism and alcohols (PDO, BDO) production.

Metabolic engineering of Klebsiella pneumoniae and in silico investigation for enhanced 2,3-butanediol production.

Objectives: To improve the production of 2,3-butanediol (2,3-BD) in Klebsiella pneumoniae, the genes related to the formation of lactic acid, ethanol, and acetic acid were eliminated.

Results: Although the cell growth and 2,3-BD production rates of the K. pneumoniae ΔldhA ΔadhE Δpta-ackA strain were lower than those of the wild-type strain, the mutant produced a higher titer of 2,3-BD and a higher yield in batch fermentation: 91 g 2,3-BD/l with a yield of 0.

Enhanced production of (R,R)-2,3-butanediol by metabolically engineered Klebsiella oxytoca.

Microbial fermentation produces a racemic mixture of 2,3-butanediol ((R,R)-BD, (S,S)-BD, and meso-BD), and the compositions and physiochemical properties vary from microorganism to microorganism. Although the meso form is much more difficult to transport and store because of its higher freezing point than those of the optically active forms, most microorganisms capable of producing 2,3-BD mainly yield meso-2,3-BD. Thus, we developed a metabolically engineered (R,R)-2,3-BD overproducing strain using a Klebsiella oxytoca ΔldhA ΔpflB strain, which shows an outstanding 2,3-BD production performance with more than 90 % of the meso form.

Identification of acetoin reductases involved in 2,3-butanediol pathway in Klebsiella oxytoca.

The acetoin reductase (AR) of Klebsiella oxytoca is responsible for converting acetoin into 2,3-butanediol (2,3-BDO) during sugar fermentation. Deleting the AR encoding gene (budC) in the 2,3-BDO operon does not block production of 2,3-BDO, as another similar gene exists in addition to budC called diacetyl/acetoin reductase (dar) which shares 53% identity with budC. In the present study, both budC and dar of K.

Production of 3-hydroxypropionic acid from glycerol by recombinant Pseudomonas denitrificans.

3-Hydroxypropionic acid (3-HP) can be produced from glycerol through two sequential enzymatic reactions that are catalyzed by a coenzyme B12 -dependent glycerol dehydratase and an NAD(P)(+) -dependent aldehyde dehydrogenase (ALDH), respectively. Pseudomonas denitrificans synthesizes coenzyme B12 under aerobic conditions, where NAD(P)(+) is regenerated efficiently. Hence, it is considered an ideal host for the production of 3-HP from glycerol under aerobic conditions.

Metabolic engineering of a novel Klebsiella oxytoca strain for enhanced 2,3-butanediol production.

Fermentative 2,3-butanediol (2,3-BD) production has been receiving increasing interest for its potential as a platform chemical intended for the production of synthetic rubbers, plastics, and solvents. In this study, Klebsiella oxytoca GSC 12206, a 2,3-BD native hyper-producing and nonpathogenic bacterium, was isolated from a cattle farm. Since this isolate produced a significant amount of lactic acid along with 2,3-BD, its mutant deficient in lactic acid formation was constructed by disrupting the ldhA gene which encodes lactate dehydrogenase.

Fermentation and evaluation of Klebsiella pneumoniae and K. oxytoca on the production of 2,3-butanediol.

Klebsiella is one of the genera that has shown unbeatable production performance of 2,3-butanediol (2,3-BD), when compared to other microorganisms. In this study, two Klebsiella strains, K. pneumoniae (DSM 2026) and K.

Production of 3-hydroxypropionic acid via malonyl-CoA pathway using recombinant Escherichia coli strains.

Malonyl-CoA is an intermediary compound that is produced during fatty acid metabolism. Our study aimed to produce the commercially important platform chemical 3-hydroxypropionic acid (3-HP) from its immediate precursor malonyl-CoA by recombinant Escherichia coli strains heterologously expressing the mcr gene of Chloroflexus aurantiacus DSM 635, encoding an NADPH-dependent malonyl-CoA reductase (MCR). The recombinant E.

Development of recombinant Klebsiella pneumoniae ∆dhaT strain for the co-production of 3-hydroxypropionic acid and 1,3-propanediol from glycerol.

Klebsiella pneumoniae converts glycerol to the specialty chemical 1,3-propanediol (1,3-PDO), which is used for the production of polytrimethylene terepthalate (PTT). In this study, an NAD(+)-dependent gamma-glutamyl-gamma-aminobutyraldehyde dehydrogenase (PuuC) of K. pneumoniae DSM 2026, which oxidizes 3-hydroxypropionaldehyde to a platform chemical 3-hydroxypropionic acid (3-HP), was cloned and overexpressed in K.

Development and evaluation of efficient recombinant Escherichia coli strains for the production of 3-hydroxypropionic acid from glycerol.

3-Hydroxypropionic acid (3-HP) is a commercially valuable chemical with the potential to be a key building block for deriving many industrially important chemicals. However, its biological production has not been well documented. Our previous study demonstrated the feasibility of producing 3-HP from glycerol using the recombinant Escherichia coli SH254 expressing glycerol dehydratase (DhaB) and aldehyde dehydrogenase (AldH), and reported that an "imbalance between the two enzymes" and the "instability of the first enzyme DhaB" were the major factors limiting 3-HP production.

Effect of process parameters on 3-hydroxypropionic acid production from glycerol using a recombinant Escherichia coli.

The top-valued platform chemical, 3-hydroxypropionic acid (3-HP), has a wide range of industrial applications but its biological production is not well established. Previously, the production of 3-HP from glycerol was demonstrated using a recombinant Escherichia coli strain expressing glycerol dehydratase (dhaB) and aldehyde dehydrogenase (aldH). The present investigation focuses on the effect of the culture conditions on the production of 3-HP from glycerol.

Cloning, expression, and characterization of an aldehyde dehydrogenase from Escherichia coli K-12 that utilizes 3-Hydroxypropionaldehyde as a substrate.

3-Hydroxypropionaldehyde (3-HPA), an intermediary compound of glycerol metabolism in bacteria, serves as a precursor to 3-Hydroxypropionic acid (3-HP), a commercially valuable platform chemical. To achieve the effective conversion of 3-HPA to 3-HP, an aldH gene encoding an aldehyde dehydrogenase in Escherichia coli K-12 (AldH) was cloned, expressed, and characterized for its properties. The recombinant AldH exhibited broad substrate specificity for various aliphatic and aromatic aldehydes.