Inhibitory effects of sulfur compounds on methane oxidation by a methane-oxidizing consortium

Eun Hee Lee, Kyung Eun Moon, Tae Gwan Kim, Sang Don Lee, Kyung Suk Cho

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Kinetic and enzymatic inhibition experiments were performed to investigate the effects of methanethiol (MT) and hydrogen sulfide (H2S) on methane oxidation by a methane-oxidizing consortium. In the coexistence of MT and H2S, the oxidation of methane was delayed until MT and H2S were completely degraded. MT and H2S could be degraded, both with and without methane. The kinetic analysis revealed that the methane-oxidizing consortium showed a maximum methane oxidation rate (Vmax) of 3.7 mmol g-dry cell weight (DCW)-1 h-1 and a saturation constant (Km) of 184.1 μM. MT and H2S show competitive inhibition on methane oxidation, with inhibition values (Ki) of 1504.8 and 359.8 μM, respectively. MT was primary removed by particulate methane monooxygenases (pMMO) of the consortium, while H2S was degraded by the other microorganisms or enzymes in the consortium. DNA and mRNA transcript levels of the pmoA gene expressions were decreased to ~106 and 103 pmoA gene copy number g-DCW-1 after MT and H2S degradation, respectively; however, both the amount of the DNA and mRNA transcript recovered their initial levels of ~107 and 105 pmoA gene copy number g-DCW-1 after methane oxidation, respectively. The gene expression results indicate that the pmoA gene could be rapidly reproducible after methane oxidation. This study provides comprehensive information of kinetic interactions between methane and sulfur compounds.

Original languageEnglish
Pages (from-to)670-676
Number of pages7
JournalJournal of Bioscience and Bioengineering
Volume120
Issue number6
DOIs
StatePublished - Dec 2015

Keywords

  • Hydrogen sulfide
  • Interaction
  • Methane
  • Methanethiol
  • Particulate methane monooxygenases

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