Role of cytochrome bd oxidase from Corynebacterium glutamicum in growth and lysine production.
Corynebacterium glutamicum possesses two terminal oxidases, cytochrome aa3 and cytochrome bd. Cytochrome aa3 forms a supercomplex with the cytochrome bc1 complex, which contains an unusual diheme cytochrome c1. Both the bc1 -aa3 supercomplex and cytochrome bd transfer reducing equivalents from menaquinol to oxygen; however, they differ in their proton translocation efficiency by a factor of three. Here, we analyzed the role of cytochrome bd for growth and lysine production. When cultivated in glucose minimal medium, a cydAB deletion mutant of C. glutamicum ATCC 13032 grew like the wild type in the exponential phase, but growth thereafter was inhibited, leading to a biomass formation 40% less than that of the wild type. Constitutive overproduction of functional cytochrome bd oxidase in ATCC 13032 led to a reduction of the growth rate by approximately 45% and of the maximal biomass by approximately 35%, presumably as a consequence of increased electron flow through the inefficient cytochrome bd oxidase. In the L-lysine-producing C. glutamicum strain MH20-22B, deletion of the cydAB genes had only minor effects on growth rate and biomass formation, but lysine production was increased by approximately 12%. Thus, the respiratory chain was shown to be a target for improving amino acid production by C. glutamicum.
Kabus
Armin
A
Institut für Biotechnologie 1, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Niebisch
Axel
A
Bott
Michael
M
D018533:Biomass; D001709:Biotechnology / Q000379:methods; D048230:Corynebacterium glutamicum / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism; D003470:Culture Media; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D008239:Lysine / Q000096:biosynthesis*; D010101:Oxygen Consumption
D003470:Culture Media; D003576:Electron Transport Complex IV; D008239:Lysine