Homolactate fermentation by metabolically engineered Escherichia coli strains

dc.contributor.author	Zhu, Y	en
dc.contributor.author	Eiteman, MA	en
dc.contributor.author	DeWitt, K	en
dc.contributor.author	Altman, E	en
dc.date.accessioned	2014-06-06T06:47:23Z
dc.date.available	2014-06-06T06:47:23Z
dc.date.issued	2007	en
dc.identifier.issn	00992240	en
dc.identifier.uri	http://dx.doi.org/10.1128/AEM.02022-06	en
dc.identifier.uri	http://62.217.125.90/xmlui/handle/123456789/3568
dc.subject.other	Anaerobic phase	en
dc.subject.other	Glyosylate	en
dc.subject.other	Succinates	en
dc.subject.other	Tricarbosylic acid	en
dc.subject.other	Biochemistry	en
dc.subject.other	Density (optical)	en
dc.subject.other	Enzymes	en
dc.subject.other	Fermentation	en
dc.subject.other	Metabolism	en
dc.subject.other	Mutagenesis	en
dc.subject.other	Nuclear magnetic resonance	en
dc.subject.other	Escherichia coli	en
dc.subject.other	formate acetyltransferase	en
dc.subject.other	formic acid derivative	en
dc.subject.other	glyoxylic acid	en
dc.subject.other	lactic acid	en
dc.subject.other	lyase	en
dc.subject.other	oxaloacetic acid	en
dc.subject.other	pyruvate dehydrogenase	en
dc.subject.other	pyruvate oxidase	en
dc.subject.other	pyruvate synthase	en
dc.subject.other	succinic acid	en
dc.subject.other	unclassified drug	en
dc.subject.other	anoxic conditions	en
dc.subject.other	bacterium	en
dc.subject.other	enzyme	en
dc.subject.other	fermentation	en
dc.subject.other	genetic engineering	en
dc.subject.other	mutation	en
dc.subject.other	aceE gene	en
dc.subject.other	aceF gene	en
dc.subject.other	aerobic fermentation	en
dc.subject.other	anaerobic fermentation	en
dc.subject.other	article	en
dc.subject.other	bacterial gene	en
dc.subject.other	bacterial growth	en
dc.subject.other	bacterial metabolism	en
dc.subject.other	bacterial strain	en
dc.subject.other	carbon nuclear magnetic resonance	en
dc.subject.other	citric acid cycle	en
dc.subject.other	Escherichia coli	en
dc.subject.other	fermentation	en
dc.subject.other	gene mutation	en
dc.subject.other	genetic code	en
dc.subject.other	genetic engineering	en
dc.subject.other	isotope labeling	en
dc.subject.other	nonhuman	en
dc.subject.other	optical density	en
dc.subject.other	pfl gene	en
dc.subject.other	poxB gene	en
dc.subject.other	pps gene	en
dc.subject.other	strain difference	en
dc.subject.other	Aerobiosis	en
dc.subject.other	Anaerobiosis	en
dc.subject.other	Bacterial Proteins	en
dc.subject.other	Culture Media	en
dc.subject.other	Escherichia coli	en
dc.subject.other	Fermentation	en
dc.subject.other	Gene Expression Regulation, Bacterial	en
dc.subject.other	Genetic Engineering	en
dc.subject.other	Industrial Microbiology	en
dc.subject.other	Lactates	en
dc.subject.other	Magnetic Resonance Spectroscopy	en
dc.subject.other	Mutation	en
dc.subject.other	Escherichia coli	en
dc.title	Homolactate fermentation by metabolically engineered Escherichia coli strains	en
heal.type	journalArticle	en
heal.identifier.primary	10.1128/AEM.02022-06	en
heal.publicationDate	2007	en
heal.abstract	We report the homofermentative production of lactate in Escherichia coli strains containing mutations in the aceEF, pfl, poxB, and pps genes, which encode the pyruvate dehydrogenase complex, pyruvate formate lyase, pyruvate oxidase, and phosphoenolpyruvate synthase, respectively. The process uses a defined medium and two distinct fermentation phases: aerobic growth to an optical density of about 30, followed by nongrowth, anaerobic production. Strain YYC202 (aceEF pfl poxB pps) generated 90 g/liter lactate in 16 h during the anaerobic phase (with a yield of 0.95 g/g and a productivity of 5.6 g/liter · h). Ca(OH)2 was found to be superior to NaOH for pH control, and interestingly, significant succinate also accumulated (over 7 g/liter) despite the use of N2 for maintaining anaerobic conditions. Strain ALS961 (YYC202 ppc) prevented succinate accumulation, but growth was very poor. Strain ALS974 (YVC202 frd ABCD) reduced succinate formation by 70% to less than 3 g/liter. 13C nuclear magnetic resonance analysis using uniformly labeled acetate demonstrated that succinate formation by ALS974 was biochemically derived from acetate in the medium. The absence of uniformly labeled succinate, however, demonstrated that glyosylate did not reeaier the tricarbosylic acid cycle via oxaloacetate. By minimizing the residual acetate at the time that the production phase commenced, the process with ALS974 achieved 138 g/liter lactate (1.55 M, 97% of the carbon products), with a yield of 0.99 g/g and a productivity of 6.3 g/liter · h during the anaerobic phase. Copyright © 2007, American Society for Microbiology. All Rights Reserved.	en
heal.journalName	Applied and Environmental Microbiology	en
dc.identifier.issue	2	en
dc.identifier.volume	73	en
dc.identifier.doi	10.1128/AEM.02022-06	en
dc.identifier.spage	456	en
dc.identifier.epage	464	en