Selective Enrichment of Methylococcaceae versus Methylocystaceae Methanotrophs via Control of Methane Feeding Schemes

authored by

Ju Yong Lee, Munjeong Choi, Min Joon Song, Daehyun Daniel Kim, Taeho Yun, Jin Chang, Adrian Ho, Jaewook Myung, Sukhwan Yoon

Abstract

Methanotrophs are crucial in keeping environmental CH₄ emissions in check. However, the contributions of different groups of methanotrophs at terrestrial CH₄-oxidation hotspots, such as the oxic-anoxic interface of rice paddies, have shown considerable inconsistency across observations. To address the knowledge gap regarding this inconsistency, methanotrophic microbiomes were enriched from paddy soils in well-mixed CH₄-fed batch reactors under six different incubation conditions, prepared as combinations of two CH₄ mixing ratios (0.5 and 10%) and three supplemented Cu²⁺ concentrations (0, 2, and 10 μM). Monitoring of temporal community shifts in these cultures revealed a dominance of Methylocystis spp. in all 0.5%-CH₄ cultures, while methanotrophs affiliated to Gammaproteobacteria dominated the 10%-CH₄ cultures that were less consistent both temporally and across conditions. The shotgun metagenome analyses of the 0.5%-CH₄ cultures corroborated the Methylocystis dominance and, interestingly, showed that copper deficiency did not select for mmoXYZ-possessing methanotrophs. Instead, a mbn cluster, accounting for approximately 5% of the Methylocystis population, was identified, suggesting the ecological significance of methanobactin in Cu-deficient methanotrophy. These findings underscore the important role of Methylocystis spp. in mitigating emissions from terrestrial CH₄ hotspots and suggest the feasibility of directed enrichment and/or isolation of Methylocystis spp. for utilization in, for example, methanobactin and polyhydroxybutyrate production.

Organisation(s)

Institute of Microbiology

External Organisation(s)

Korea Advanced Institute of Science and Technology (KAIST)
University of California at Berkeley

Type

Article

Journal

Environmental Science and Technology

Volume

58

Pages

14237-14248

No. of pages

12

ISSN

0013-936X

Publication date

13.08.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Chemistry, Environmental Chemistry

Electronic version(s)

https://doi.org/10.1021/acs.est.4c02655 (Access: Closed)