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DC Field | Value | Language |
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dc.citation.endPage | 724 | - |
dc.citation.number | 5 | - |
dc.citation.startPage | 717 | - |
dc.citation.title | JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY | - |
dc.citation.volume | 13 | - |
dc.contributor.author | Kim, JR | - |
dc.contributor.author | Oh, YK | - |
dc.contributor.author | Yoon, YJ | - |
dc.contributor.author | Lee, EY | - |
dc.contributor.author | Park, Sunghoon | - |
dc.date.accessioned | 2023-12-22T11:08:52Z | - |
dc.date.available | 2023-12-22T11:08:52Z | - |
dc.date.created | 2017-06-14 | - |
dc.date.issued | 2003-10 | - |
dc.description.abstract | A newly isolated Citrobacter sp. Y19 catalyzes the CO-dependent H-2 production (biological water-gas shift reaction) by the actions of CO dehydrogenase (CODH) and hydrogenase. Y19 requires O-2 for fast growth, but its H-2 production activity is significantly inhibited by O-2. In the present study, the effect of O-2 on the activities of CODH and hydrogenase was investigated quantitatively in both whole cells and broken cells, based on CO-dependent or methyl viologen (MV)-dependent H-2 production in addition to CO-dependent MV reduction. In crude cell extracts, CODH activity was mostly found in the soluble fraction. Inactivation of CODH and hydrogenase activities by O-2 followed the first-order decay kinetics, and the dependence of the rate constants on O-2 partial pressure could be expressed by the Michaelis-Menten equation. In whole cells, the maximum deactivation rate constants (k(d.max)) of hydrogenase and CODH were quite similar: 0.07 +/- 0.03 min' and 0.10 +/- 0.04 min(-1), respectively. However, the first-order rate constant (k(d.max)/K-s) of CODH (0.25 min(-1) atm(-1)) at low O-2 partial pressures was about 3-fold higher than that of the hydrogenase, since the half-saturation constant (K-s) of CODH was about half of that of hydrogenase. In broken cells, both enzymes became significantly more sensitive to O-2 compared to the unbroken cells, while k(d,max)/K-s increased 37-fold for hydrogenase and 6.7-fold for CODH. When whole cells were incubated under anaerobic conditions after being exposed to air for 1 h, hydrogenase activity was recovered more than 90% in 2 h suggesting that the deactivation of hydrogenase by O-2 was reversible. On the contrary, CODH activity was not recovered once deactivated by O-2, and the only way to recover the activity was to synthesize new CODH. This study indicates that O-2 sensitivity of H-2 production activity of Citrobacter Y19 is an important drawback as in other H-2-producing bacteria. | - |
dc.identifier.bibliographicCitation | JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY, v.13, no.5, pp.717 - 724 | - |
dc.identifier.issn | 1017-7825 | - |
dc.identifier.scopusid | 2-s2.0-0242720433 | - |
dc.identifier.uri | https://scholarworks.unist.ac.kr/handle/201301/25392 | - |
dc.identifier.wosid | 000186209200013 | - |
dc.language | 영어 | - |
dc.publisher | KOREAN SOC MICROBIOLOGY & BIOTECHNOLOGY | - |
dc.title | Oxygen sensitivity of carbon monoxide-dependent hydrogen production activity in Citrobacter sp. | - |
dc.type | Article | - |
dc.description.journalRegisteredClass | scie | - |
dc.description.journalRegisteredClass | scopus | - |
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