title: Methylglyoxal bypass identified as source of chiral contamination in l(+) and d(-)-lactate fermentations by recombinant Escherichia coli.
abstract: Two new strains of Escherichia coli B were engineered for the production of lactate with no detectable chiral impurity. All chiral impurities were eliminated by deleting the synthase gene (msgA) that converts dihydroxyacetone-phosphate to methylglyoxal, a precursor for both L: (+)- and D: (-)-lactate. Strain TG113 contains only native genes and produced optically pure D: (-)-lactate. Strain TG108 contains the ldhL gene from Pediococcus acidilactici and produced only L: (+)-lactate. In mineral salts medium containing 1 mM betaine, both strains produced over 115 g (1.3 mol) lactate from 12% (w/v) glucose, >95% theoretical yield.
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
authors.forename: T B
authors.initials: TB
authors.lastname: Grabar
authors.forename: S
authors.initials: S
authors.lastname: Zhou
authors.forename: K T
authors.initials: KT
authors.lastname: Shanmugam
authors.forename: L P
authors.initials: LP
authors.lastname: Yomano
authors.forename: L O
authors.initials: LO
authors.lastname: Ingram
mesh_terms: D001709:Biotechnology / Q000379:methods*; D019757:Carbon-Oxygen Lyases / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D017353:Gene Deletion; D006019:Glycolysis / Q000235:genetics; D007218:Industrial Microbiology; D019344:Lactic Acid / Q000096:biosynthesis* / Q000737:chemistry; D011765:Pyruvaldehyde / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D011994:Recombinant Proteins; D019344:Lactic Acid; D011765:Pyruvaldehyde; D019757:Carbon-Oxygen Lyases; C021578:methylglyoxal synthase