121st General Meeting of the KCS

Type Symposium
Area Current Trends in Environmental and Energy Chemistry
Room No. Room 201B
Time THU 15:40-:
Code ENVR1-1
Subject The effects of methanobactin secreted by Alphaproteobacterial methanotrophs on N2O emissions from denitrifiers
Authors Sukhwan Yoon
Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Korea
Abstract Methanobactin (Mb) is a Cu chelator secreted by methanotrophs for scavenging of Cu from Cu-deficient environments. Cu scavenging may result in deprivation of Cu from the environment and thus, may have a negative impact on the biogeochemical reactions that require Cu for their activities. N2O reduction mediated by nitrous oxide reductase (N2OR) is one of such Cu-dependent reactions, which has an environmentally significant function of reducing N2O emissions. This study investigated the effect of methanobactin secretion by Alphaproteobacterial methanotrophs on N2O emissions from denitrifying microorganisms. In the experiments performed with model strains of a methanotroph (Methylosinus trichosporium OB3b) and a denitrifier (Pseudomonas stutzeri DCP-Ps1), permanent N2O production resulted from P. stutzeri culture incubated with the O2-depleted M. trichosporium culture, while no significant N2O accumulation was observed when the mutant strain (mbnA- strain) with a defunct methanobactin production pathway was used in place of the wildtype strain OB3b. The similar enhancement of N2O emission was observed with environmental samples with complex microbial communities when they were enriched for Alphaproteobacterial methanotrophs before introduction of anoxia. These observations suggest that such involuntary inhibition of N2O reduction is a plausible mechanism of N2O emissions at oxic-anoxic interfaces in the environments where methanotrophy and denitrification may simultaneously occur, e.g., rice paddy soils and landfill cover soils.
E-mail syoon80@kaist.ac.kr