Enhanced valine production in Corynebacterium glutamicum with defective H+-ATPase and C-terminal truncated acetohydroxyacid synthase.
We have reported increased glutamate production by a mutant of Corynebacterium glutamicum ATCC14067 (strain F172-8) with reduced H(+)-ATPase activity under biotin-limiting culture conditions (Aoki et al. Biosci. Biotechnol. Biochem., 69, 1466-1472 (2005)). In the present study, we examined valine production by an H(+)-ATPase-defective mutant of C. glutamicum. Using the double-crossover chromosome replacement technique, we constructed a newly defined H(+)-ATPase-defective mutant from ATCC13032. After transforming the new strain (A-1) with a C-terminal truncation of acetohydroxyacid synthase gene (ilvBN), valine production increased from 21.7 mM for the wild-type strain to 46.7 mM for the A-1 in shaking flask cultures with 555 mM glucose. Increased production of the valine intermediate acetoin was also observed in A-1, and was reduced by inserting acetohydroxyacid isomeroreductase gene (ilvC) into the ilvBN plasmid. After transformation with this new construct, valine production increased from 38.3 mM for the wild-type strain to 95.7 mM for A-1 strain. To the best of our knowledge, this is the first report indicating that an H(+)-ATPase-defective mutant of C. glutamicum is capable of valine production. Our combined results with glutamate and valine suggest that the H(+)-ATPase defect is also effective in the fermentative production of other practical compounds.
Wada
Masaru
M
Division of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan. wada@chem.agr.hokudai.ac.jp
Hijikata
Nowaki
N
Aoki
Ryo
R
Takesue
Nobuchika
N
Yokota
Atsushi
A
D000095:Acetolactate Synthase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D005818:Genetic Engineering; D050540:Ketol-Acid Reductoisomerase / Q000235:genetics; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D014633:Valine / Q000096:biosynthesis*
D050540:Ketol-Acid Reductoisomerase; D000095:Acetolactate Synthase; D006180:Proton-Translocating ATPases; D014633:Valine