On February 29, 2012, Siedler, Solvej; Bringer, Stephanie; Blank, Lars M.; Bott, Michael published an article.Safety of (R)-Methyl 3-hydroxybutanoate The title of the article was Engineering yield and rate of reductive biotransformation in Escherichia coli by partial cyclization of the pentose phosphate pathway and PTS-independent glucose transport. And the article contained the following:
Optimization of yields and productivities in reductive whole-cell biotransformations is an important issue for the industrial application of such processes. In a recent study with Escherichia coli, we analyzed the reduction of the prochiral β-ketoester Me acetoacetate by an R-specific alc. dehydrogenase (ADH) to the chiral hydroxy ester (R)-Me 3-hydroxybutyrate (MHB) using glucose as substrate for the generation of NADPH. Deletion of the phosphofructokinase gene pfkA almost doubled the yield to 4.8 mol MHB per mol of glucose, and it was assumed that this effect was due to a partial cyclization of the pentose phosphate pathway (PPP). Here, this partial cyclization was confirmed by 13C metabolic flux anal., which revealed a neg. net flux from glucose 6-phosphate to fructose 6-phosphate catalyzed by phosphoglucose isomerase. For further process optimization, the genes encoding the glucose facilitator (glf) and glucokinase (glk) of Zymomonas mobilis were overexpressed in recombinant E. coli strains carrying ADH and deletions of either pgi (phosphoglucose isomerase), or pfkA, or pfkA plus pfkB. In all cases, the glucose uptake rate was increased (30-47%), and for strains Δpgi and ΔpfkA also, the specific MHB production rate was increased by 15% and 20%, resp. The yield of the latter two strains slightly dropped by 11% and 6%, but was still 73% and 132% higher compared to the reference strain with intact pgi and pfkA genes and expressing glf and glk. Thus, metabolic engineering strategies are presented for improving yield and rate of reductive redox biocatalysis by partial cyclization of the PPP and by increasing glucose uptake, resp. The experimental process involved the reaction of (R)-Methyl 3-hydroxybutanoate(cas: 3976-69-0).Safety of (R)-Methyl 3-hydroxybutanoate
The Article related to metabolic engineering escherichia partial cyclization pentose phosphate pathway glucose, Fermentation and Bioindustrial Chemistry: Other and other aspects.Safety of (R)-Methyl 3-hydroxybutanoate
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