Methane, a potent greenhouse gas, is a significant contributor to global warming. One of the primary natural sinks for atmospheric methane is forest soils, which, teeming with special microorganisms, actively consume methane through a process called methanotrophy. However, this natural balance is being disrupted mainly by the conversion of forest lands into agricultural areas. This land-use change often leads to a reduction in the area covered by methane-consuming soils, exacerbating the overall methane emissions problem.

Chernevaya Taiga is a unique forest ecosystem in Siberia, known for intense microbial activity related to the nitrogen and carbon cycles. However, studies focusing on methane cycling and the isolation of methanotrophs within these forests have not been conducted. We hypothesized that active methanotrophs might be present in these soils with specialized adaptations to harsh environmental conditions.

We isolated methanotrophic consortium; T1 exhibited exceptionally high methane oxidation rates from the dark gray soil of the Сhernevaya taiga, Tomsk region. 16S rRNA gene profiling revealed the predominance (74%) of Methylocystis. It was established that the introduction of the T1 into the agrosoil with low methane oxidation activity resulted in an increased methane uptake rate. Furthermore, measuring the accumulation of CO₂ in the samples correlates well with the methane oxidation rate and confirms the high activity of the introduced culture as a methane sink. Nevertheless, the number of 16S rRNA gene copies reached 3.9 × 10⁹ and changed minimally over a period of four weeks. Concurrently, the number of pmoA gene copies remained at a relatively high level of 8.81 × 10⁵ – 1.47 × 10⁶, which indicates the significant presence of methanotrophs within the agrosoil microbial community.

The research was funded by a grant # 25-24-20102 of the Russian Science Foundation (https://rscf.ru/en/project/25-24-20102/).