RRC ID 27479
著者 Hasegawa S, Suda M, Uematsu K, Natsuma Y, Hiraga K, Jojima T, Inui M, Yukawa H.
タイトル Engineering of Corynebacterium glutamicum for high-yield L-valine production under oxygen deprivation conditions.
ジャーナル Appl Environ Microbiol
Abstract We previously demonstrated efficient L-valine production by metabolically engineered Corynebacterium glutamicum under oxygen deprivation. To achieve the high productivity, a NADH/NADPH cofactor imbalance during the synthesis of l-valine was overcome by engineering NAD-preferring mutant acetohydroxy acid isomeroreductase (AHAIR) and using NAD-specific leucine dehydrogenase from Lysinibacillus sphaericus. Lactate as a by-product was largely eliminated by disrupting the lactate dehydrogenase gene ldhA. Nonetheless, a few other by-products, particularly succinate, were still produced and acted to suppress the L-valine yield. Eliminating these by-products therefore was deemed key to improving theL-valine yield. By additionally disrupting the phosphoenolpyruvate carboxylase gene ppc, succinate production was effectively suppressed, but both glucose consumption and L-valine production dropped considerably due to the severely elevated intracellular NADH/NAD(+) ratio. In contrast, this perturbed intracellular redox state was more than compensated for by deletion of three genes associated with NADH-producing acetate synthesis and overexpression of five glycolytic genes, including gapA, encoding NADH-inhibited glyceraldehyde-3-phosphate dehydrogenase. Inserting feedback-resistant mutant acetohydroxy acid synthase and NAD-preferring mutant AHAIR in the chromosome resulted in higher L-valine yield and productivity. Deleting the alanine transaminase gene avtA suppressed alanine production. The resultant strain produced 1,280 mM L-valine at a yield of 88% mol mol of glucose(-1) after 24 h under oxygen deprivation, a vastly improved yield over our previous best.
巻・号 79(4)
ページ 1250-7
公開日 2013-2-1
DOI 10.1128/AEM.02806-12
PII AEM.02806-12
PMID 23241971
PMC PMC3568611
MeSH Anaerobiosis Biosynthetic Pathways / genetics* Corynebacterium glutamicum / genetics* Corynebacterium glutamicum / metabolism* Gene Deletion Gene Expression Lactic Acid / metabolism Metabolic Engineering* NAD / metabolism Oxygen / metabolism Recombination, Genetic Succinic Acid / metabolism Valine / biosynthesis*
IF 4.016
引用数 71
WOS 分野 BIOTECHNOLOGY & APPLIED MICROBIOLOGY MICROBIOLOGY
リソース情報
一般微生物 JCM 18229