In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 81, No. 5 ( 2015-03), p. 1708-1714
Abstract:
Genome analysis revealed the existence of a putative transcriptional regulatory system governing CO metabolism in Thermococcus onnurineus NA1, a carboxydotrophic hydrogenogenic archaeon. The regulatory system is composed of CorQ with a 4-vinyl reductase domain and CorR with a DNA-binding domain of the LysR-type transcriptional regulator family in close proximity to the CO dehydrogenase (CODH) gene cluster. Homologous genes of the CorQR pair were also found in the genomes of Thermococcus species and “ Candidatus Korarchaeum cryptofilum” OPF8. In-frame deletion of either corQ or corR caused a severe impairment in CO-dependent growth and H 2 production. When corQ and corR deletion mutants were complemented by introducing the corQR genes under the control of a strong promoter, the mRNA and protein levels of the CODH gene were significantly increased in a ΔCorR strain complemented with integrated corQR (ΔCorR/ corQR ↑ ) compared with those in the wild-type strain. In addition, the ΔCorR/ corQR ↑ strain exhibited a much higher H 2 production rate (5.8-fold) than the wild-type strain in a bioreactor culture. The H 2 production rate (191.9 mmol liter −1 h −1 ) and the specific H 2 production rate (249.6 mmol g −1 h −1 ) of this strain were extremely high compared with those of CO-dependent H 2 -producing prokaryotes reported so far. These results suggest that the corQR genes encode a positive regulatory protein pair for the expression of a CODH gene cluster. The study also illustrates that manipulation of the transcriptional regulatory system can improve biological H 2 production.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.03019-14
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2015
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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