Degradation of Ethanol and Ethanethiol By Methanosarcina Horinobensis

Abstract

In this study, Methanosarcina horinobensis was used as the object to explore the degradation mechanism of sulfur-containing small molecular organics (ethanethiol, ethanol, etc.) and the formation process of hydrogen sulfide (H₂S) and methane (CH₄) under strict anaerobic conditions. Through anaerobic fermentation experiments, combined with gas chromatograph and ion chromatograph analysis of gas and liquid phase composition changes, it was found that when ethanol was used as the substrate, the methanogenic capacity of the flora reached a peak at 14~26 days, and the cumulative gas production was 21.317 mL/g, and the concentration of CO₂ fluctuated. When ethanethiol was used as the substrate, the production of H 2 S reached the peak (6.78 mL/g ) in the first 4 days of fermentation, and the production of CH was weak (0.00116 mL/g), and the peak period of the two was consistent. The liquid phase analysis showed that the concentration change of sulfur-containing inorganic ions (such as SO₄^2- and S₂O₃^2- ) was not directly related to the formation of H₂S, suggesting that the degradation of ethanethiol directly generated H₂S and CH₄. The study revealed that the strain catalyzed the decomposition of methyl compounds by methyltransferase, and used HS-CoM as an electron donor to convert methyl groups into CH₄, accompanied by the formation of H₂S. The conclusion shows that methanogens can directly use sulfur-containing methyl compounds, which provides a theoretical basis for revealing the biological origin and control technology of H₂S in coal seams.