Expression of amplified synthetic ethanol pathway integrated using Tn7-tool and powered at the expense of eliminated pta, ack, spo0A and spo0J during continuous syngas or CO2/H2 blend fermentation
Article first published online: 1 FEB 2013
© 2013 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 114, Issue 4, pages 1033–1045, April 2013
How to Cite
Kiriukhin, M. and Tyurin, M. (2013), Expression of amplified synthetic ethanol pathway integrated using Tn7-tool and powered at the expense of eliminated pta, ack, spo0A and spo0J during continuous syngas or CO2/H2 blend fermentation. Journal of Applied Microbiology, 114: 1033–1045. doi: 10.1111/jam.12123
- Issue published online: 18 MAR 2013
- Article first published online: 1 FEB 2013
- Accepted manuscript online: 5 JAN 2013 02:40AM EST
- Manuscript Accepted: 24 DEC 2012
- Manuscript Revised: 8 DEC 2012
- Manuscript Received: 24 OCT 2012
- ack ;
- gene elimination;
- pta ;
- syngas fermentation
To engineer acetogen biocatalyst selectively overproducing ethanol from synthesis gas or CO2/H2 as the only liquid carbonaceous product.
Methods and Results
Ethanol-resistant mutant originally capable of producing only acetate from CO2/CO was engineered to eliminate acetate production and spore formation using our proprietary Cre-lox66/lox71-system. Bi-functional aldehyde/alcohol dehydrogenase was inserted into the chromosome of the engineered mutant using Tn7-based approach. Recombinants with three or six copies of the inserted gene produced 525 mmol l−1 and 1018 mmol l−1 of ethanol, respectively, in five independent single-step fermentation runs 25 days each (P < 0·005) in five independent repeats using syngas blend 60% CO and 40% H2. Ethanol production was 64% if only CO2 + H2 blend was used compared with syngas blend (P < 0·005).
Elimination of genes unnecessary for syngas fermentation can boost artificial integrated pathway performance.
Significance and Impact of the Study
Cell energy released via elimination of phosphotransacetylase, acetate kinase and early-stage sporulation genes boosted ethanol production. Deletion of sporulation genes added theft-proof feature to the engineered biocatalyst. Production of ethanol from CO2/H2 blend might be utilized as a tool to mitigate global warming proportional to CO2 fermentation scale.