Cofactor Engineering Enhances the Physiological Function of an Industrial Strain

Liu, Li; Chen, Jian

doi:10.5772/18249

Cited by 4 publications

(5 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These approaches have been proven to be powerful in developing microbial strains for the commercial production of organic acids, amino acids, biofuels, and pharmaceuticals [2]. Nevertheless, over-expression, deletion, or introduction of heterologous genes in target metabolic pathways do not always result in the desired phenotype [3].…”

Section: Introductionmentioning

confidence: 99%

“…Manipulations of the cofactor form and level have become a useful tool for metabolic engineering to redistribute/enhance carbon flux in metabolic networks [4]. Nicotinamide adenine dinucleotides (NADH and NAD + ), as one pair of key cofactors play an important role in over 300 biochemical reactions involving oxidation and reduction [2,5]. Therefore, this cofactor pair (NADH and NAD + ) has a critical effect on maintaining the intracellular redox balance, which is a basic condition for microorganism to metabolize and grow [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cofactor engineering through heterologous expression of an NADH oxidase and its impact on metabolic flux redistribution in Klebsiella pneumoniae

Xia

et al. 2013

Biotechnol Biofuels

View full text Add to dashboard Cite

BackgroundAcetoin is an important bio-based platform chemical. However, it is usually existed as a minor byproduct of 2,3-butanediol fermentation in bacteria.ResultsThe present study reports introducing an exogenous NAD+ regeneration sysytem into a 2,3-butanediol producing strain Klebsiella pneumoniae to increse the accumulation of acetoin. Batch fermentation suggested that heterologous expression of the NADH oxidase in K. pneumoniae resulted in large decreases in the intracellular NADH concentration (1.4 fold) and NADH/NAD+ ratio (2.0 fold). Metabolic flux analysis revealed that fluxes to acetoin and acetic acid were enhanced, whereas, production of lactic acid and ethanol were decreased, with the accumualation of 2,3-butanediol nearly unaltered. By fed-batch culture of the recombinant, the highest reported acetoin production level (25.9 g/L) by Klebsiella species was obtained.ConclusionsThe present study indicates that microbial production of acetoin could be improved by decreasing the intracellular NADH/NAD+ ratio in K. pneumoniae. It demonstrated that the cofactor engineering method, which is by manipulating the level of intracellular cofactors to redirect cellular metabolism, could be employed to achieve a high efficiency of producing the NAD+-dependent microbial metabolite.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cofactor engineering through heterologous expression of an NADH oxidase and its impact on metabolic flux redistribution in Klebsiella pneumoniae

Xia

et al. 2013

Biotechnol Biofuels

View full text Add to dashboard Cite

show abstract

“…The two pyruvates that enter the 2,3-BDO biosynthetic pathway consume reducing equivalents during conversion to 2,3-BDO, and this plays an important role in regulating the intracellular NADH/NAD + ratio [ 32 ]. These two nicotinamide adenine dinucleotides (NADH and NAD + ) function as cofactors in more than 300 enzymes related to oxidation and reduction [ 33 , 34 ]. Thus, the NADH/NAD + ratio has a decisive effect on the intracellular redox balance and maintenance of the general conditions in which microorganisms can metabolize and grow [ 35 ].…”

Section: Resultsmentioning

confidence: 99%

Production of 1,2-propanediol from glycerol in Klebsiella pneumoniae GEM167 with flux enhancement of the oxidative pathway

Heo

et al. 2023

Biotechnol Biofuels

View full text Add to dashboard Cite

Background To support the sustainability of biodiesel production, by-products, such as crude glycerol, should be converted into high-value chemical products. 1,2-propanediol (1,2-PDO) has been widely used as a building block in the chemical and pharmaceutical industries. Recently, the microbial bioconversion of lactic acid into 1,2-PDO is attracting attention to overcome limitations of previous biosynthetic pathways for production of 1,2-PDO. In this study, we examined the effect of genetic engineering, metabolic engineering, and control of bioprocess factors on the production of 1,2-PDO from lactic acid by K. pneumoniae GEM167 with flux enhancement of the oxidative pathway, using glycerol as carbon source. Results We developed K. pneumoniae GEM167ΔadhE/pBR-1,2PDO, a novel bacterial strain that has blockage of ethanol biosynthesis and biosynthesized 1,2-PDO from lactic acid when glycerol is carbon source. Increasing the agitation speed from 200 to 400 rpm not only increased 1,2-PDO production by 2.24-fold to 731.0 ± 24.7 mg/L at 48 h but also increased the amount of a by-product, 2,3-butanediol. We attempted to inhibit 2,3-butanediol biosynthesis using the approaches of pH control and metabolic engineering. Control of pH at 7.0 successfully increased 1,2-PDO production (1016.5 ± 37.3 mg/L at 48 h), but the metabolic engineering approach was not successful. The plasmid in this strain maintained 100% stability for 72 h. Conclusions This study is the first to report the biosynthesis of 1,2-PDO from lactic acid in K. pneumoniae when glycerol was carbon source. The 1,2-PDO production was enhanced by blocking the synthesis of 2,3-butanediol through pH control. Our results indicate that K. pneumoniae GEM167 has potential for the production of additional valuable chemical products from metabolites produced through oxidative pathways.

show abstract

“…As a predominant redox product of catabolism, NADH plays an important role in over 700 biochemical reactions, a number of which are synthetically practical enzymatic reactions1627. Given the high cost of NADH, its stoichiometric use is not economically feasible.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, the amount of increased NADH level of E. coli BL21 (DE3) (pETDuet- bdhfdh ) might be lower. Secondly, there are systems in microbial cells for maintaining the NADH/NAD + ratio, for the homeostasis of NADH/NAD + is essential to sustain the metabolism27. As a result, the intracellular NADH concentration might be difficult to improve when it reach a high level.…”

Section: Discussionmentioning

confidence: 99%

Engineering of cofactor regeneration enhances (2S,3S)-2,3-butanediol production from diacetyl

Wang

et al. 2013

Sci Rep

View full text Add to dashboard Cite

(2S,3S)-2,3-Butanediol ((2S,3S)-2,3-BD) is a potentially valuable liquid fuel and an excellent building block in asymmetric synthesis. In this study, cofactor engineering was applied to improve the efficiency of (2S,3S)-2,3-BD production and simplify the product purification. Two NADH regeneration enzymes, glucose dehydrogenase and formate dehydrogenase (FDH), were introduced into Escherichia coli with 2,3-BD dehydrogenase, respectively. Introduction of FDH resulted in higher (2S,3S)-2,3-BD concentration, productivity and yield from diacetyl, and large increase in the intracellular NADH concentration. In fed-batch bioconversion, the final titer, productivity and yield of (2S,3S)-2,3-BD on diacetyl reached 31.7 g/L, 2.3 g/(L·h) and 89.8%, the highest level of (2S,3S)-2,3-BD production thus far. Moreover, cosubstrate formate was almost totally converted to carbon dioxide and no organic acids were produced. The biocatalytic process presented should be a promising route for biotechnological production of NADH-dependent microbial metabolites.

show abstract

Cofactor Engineering Enhances the Physiological Function of an Industrial Strain

Cited by 4 publications

References 70 publications

Cofactor engineering through heterologous expression of an NADH oxidase and its impact on metabolic flux redistribution in Klebsiella pneumoniae

Cofactor engineering through heterologous expression of an NADH oxidase and its impact on metabolic flux redistribution in Klebsiella pneumoniae

Production of 1,2-propanediol from glycerol in Klebsiella pneumoniae GEM167 with flux enhancement of the oxidative pathway

Engineering of cofactor regeneration enhances (2S,3S)-2,3-butanediol production from diacetyl

Contact Info

Product

Resources

About