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Metabolic engineering of E. coli for efficient production of glycolic acid from glucose

Author:
Deng, Yu, Mao, Yin, Zhang, Xiaojuan
Source:
Biochemical engineering journal 2015 v.103 pp. 256-262
ISSN:
1369-703X
Subject:
DNA, Escherichia coli, aeration, batch fermentation, bioreactors, chromosomes, culture flasks, gene overexpression, genes, glucose, glycolic acid, glyoxylate cycle, homologous recombination, isocitrate dehydrogenase, isocitrate lyase, malate synthase, metabolic engineering, mixing, mutants
Abstract:
Glycolic acid is the smallest member of the α-hydroxy acid family. In order to produce glycolate from glucose via the glyoxylate shunt stably, one malate synthase gene aceB in Escherichia coli BW25113 was deleted by homologous recombination; another malate synthase gene glcB was then replaced by a DNA cassette WAK harboring isocitrate lyase gene (aceA), glyoxylate reductase gene (ycdW) and isocitrate dehydrogenase kinase/phosphatase gene (aceK). The above three genes were over-expressed in the chromosome of E. coli EYX-1WAK. This strain was then transferred 20 times on M9 medium to have a mutant strain: EYX-2 with a significantly improved growth rate. The glycolate yields of EYX-2 in the shaken flasks and the 5-L bioreactor using batch fermentation strategy under 2vvm aeration and 800rpm stirring speed were 0.33g/g-glucose and 0.48g/g-glucose, respectively. The fed-batch fermentation of EYX-2 on 120g/L glucose had the highest titer of 56.44g/L with 0.52g/g-glucose yield in 120h, and this is the highest reported glycolate yield ever.
Agid:
5541781