Distribution of the methanotrophic bacteria in the Western part of the Upper Silesian Coal Basin (Borynia-Zofiówka and Budryk coal mines)

• Aerobic methanotrophic bacteria accompany coal seams in USCB.
• USCB coal beds were colonized by the methanotrophs after completion of coalification.
• USCB methanotrophs belong to α- and γ-Proteobacteria.
• Methanotrophic activity of the rock depends on identity of the methanotrophs.
• Methanotrophic activity affects methane content of the coal beds.

In the past decade, several research projects were undertaken to examine the relationship between qualitative and quantitative parameters of the coal bed gas and microbial inhabitants of the subsurface environment. Majority of the studies focused on methanogens due to their potential to improve the yields of methane extracted for industrial use, but recently it was found that the coal bearing sediments are also a habitat of the methane-oxidizing bacteria. These microbiota comprise an important element of the carbon cycle; however, so far distribution and geochemical controls of their activity were poorly recognized. The current study addresses this dearth of knowledge and provide data about distribution of aerobic methane oxidizers in the Western part of the Upper Silesian Coal Basin — one of the most important and prospective mining regions in Europe.The coal seams investigated (nos. 358, 364, 401, 405, 406, 410, 413 and 502) were of Bashkirian age and located at depths from c.a. 700 to 1000 m below surface. Methanotrophic bacteria were ubiquitous with activity ranging from 0.191 to 2.513 μM CH4 g− 1 day− 1 in the laboratory conditions (30 °C, 100% water capacity (WHC) and 10% v/v CH4). 16S rRNA sequences retrieved from the coal bed rocks revealed the presence of a variable methanotrophic community comprising of type I, II and X methanotrophs with the latter being assumed to play a dominant role in subsurface methane oxidation. It was assumed that the methanotrophic bacteria present in the Carboniferous coal deposits should be further investigated to assess their contribution to the safety of mining operations and due to their potential to be used as a biofilter for methane.