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Modification of central metabolic pathway in escherichia coli to reduce acetate accumulation by heterologous expression of the bacillus subtilis acetolactate synthase gene
Author(s) -
Aristidou Aristos A.,
San KaYiu,
Bennett George N.
Publication year - 1994
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260440810
Subject(s) - acetoin , escherichia coli , bacillus subtilis , biochemistry , enzyme , metabolic engineering , acetate kinase , acetolactate synthase , heterologous , biology , heterologous expression , phosphoenolpyruvate carboxykinase , atp synthase , metabolic pathway , citric acid cycle , chemistry , gene , fermentation , bacteria , recombinant dna , genetics
A novel metabolic engineering technique involving the redirection ofcellular carbon fluxes was employed to reduce acetate production in an Escherichia coli culture. Metabolic engineering was achieved by cloning E. coli the gene for the Bacillus subtilis acetolactate synthase (ALS), an enzyme capable of catalyzing the conversion of pyruvate to nonacidic and less harmful species. The heterologous expression of the ALS catabolic enzyme in Escherichia coli drastically modified the cellular glycolytic fluxes. In particular, acetate excretion, which is a common characteristic of E. coli , as well as a physiological burden, was minimized. The residual acetate level was kept under control and maintained at a level that was below the toxic threshold. The expression of the biologically active ALS enzyme in E. coli did not result in any detectable changes on either cell growth rate or cell yields. The alternative product, acetoin, was shown to be 50 times less harmful than acetate. Similarities in the growth pattern of two different E. coli strains, RR1 and GJT001, under all cultivation conditions suggested that the ability of ALS to reduce acetate accumulation is generic and not strain‐specific. © 1994 John Wiley & Sons, Inc.