Transcriptomic profiling and its implications for the H2production of a non-methanogen deficient in the frhAGB-encoding hydrogenase.
The F420-reducing hydrogenase of methanogens functions in methanogenesis by providing reduced coenzyme F420(F420H2) as an electron donor. In non-methanogens, however, their physiological function has not been identified yet. In this study, we constructed an ΔfrhA mutant, whose frhA gene encoding the hydrogenase α subunit was deleted, in the non-methanogenic Thermococcus onnurineus NA1 as a model organism. There was no significant difference in the formate-dependent growth between the mutant and the wild-type strains. Interestingly, the mutation in the frhA gene affected the expression of genes involved in various cellular functions such as H2oxidation, chemotactic signal transduction, and carbon monoxide (CO) metabolism. Among these genes, the CO oxidation gene cluster, enabling CO-dependent growth and H2production, showed a 2.8- to 7.0-fold upregulation by microarray-based whole transcriptome expression profiling. The levels of proteins produced by this gene cluster were also significantly increased not only under the formate condition but also under the CO condition. In a controlled bioreactor, where 100% CO was continuously fed, the ΔfrhA mutant exhibited significant increases in cell growth (2.8-fold) and H2production (3.4-fold). These findings strongly imply that this hydrogenase is functional in non-methanogens and is related to various cellular metabolic processes through an unidentified mechanism. An understanding of the mechanism by which the frhA gene deletion affected the expression of other genes will provide insights that can be applied to the development of strategies for the enhancement of H2production using CO as a substrate.
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.
Seong Hyuk
SH
Lee
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.|Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon, 34129, Republic of Korea.
Min-Sik
MS
Kim
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.|Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
Yun Jae
YJ
Kim
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea.|Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea.
Tae Wan
TW
Kim
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea. sgkang@kiost.ac.kr.|Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea. sgkang@kiost.ac.kr.
Sung Gyun
SG
Kang
Korea Institute of Ocean Science and Technology, Ansan, 15627, Republic of Korea. leeh522@kiost.ac.kr.|Department of Marine Biotechnology, Korea University of Science and Technology, Daejeon, 34113, Republic of Korea. leeh522@kiost.ac.kr.
Hyun Sook
HS
Lee
D019149:Bioreactors; D002248:Carbon Monoxide / Q000378:metabolism; D017353:Gene Deletion; D020869:Gene Expression Profiling / Q000379:methods; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D010084:Oxidation-Reduction; D019712:Thermococcus / Q000235:genetics* / Q000378:metabolism
D002248:Carbon Monoxide; D006859:Hydrogen; D006864:Hydrogenase
Carbon monoxide (CO); H2 production; Thermococcus onnurineus NA1; Transcriptome; frhAGB-encoding hydrogenase