Reducing maintenance metabolism by metabolic engineering of respiration improves riboflavin production by Bacillus subtilis.
We present redirection of electron flow to more efficient proton pumping branches within respiratory chains as a generally applicable metabolic engineering strategy, which tailors microbial metabolism to the specific requirements of high cell density processes by improving product and biomass yields. For the example of riboflavin production by Bacillus subtilis, we reduced the rate of maintenance metabolism by about 40% in a cytochrome bd oxidase knockout mutant. Since the putative Yth and the caa(3) oxidases were of minor importance, the most likely explanation for this improvement is translocation of two protons per transported electron via the remaining cytochrome aa(3) oxidase, instead of only one proton via the bd oxidase. The reduction of maintenance metabolism, in turn, significantly improved the yield of recombinant riboflavin and B. subtilis biomass in fed-batch cultures.
Institute of Biotechnology, Swiss Federal Institute of Technology Zürich, ETH Zürich, Honggerberg, CH-8093, Zürich, Switzerland.
Nicola
N
Zamboni
Nigel
N
Mouncey
Hans-Peter
HP
Hohmann
Uwe
U
Sauer
D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D019069:Cell Respiration / Q000235:genetics / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004734:Energy Metabolism / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D005818:Genetic Engineering / Q000379:methods*; D024861:Genetic Enhancement / Q000379:methods; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D015202:Protein Engineering / Q000379:methods; D017494:Proton Pumps / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012256:Riboflavin / Q000096:biosynthesis*; D013045:Species Specificity
D017494:Proton Pumps; D011994:Recombinant Proteins; D003576:Electron Transport Complex IV; D012256:Riboflavin