Evaluation of vanadium effect on methane oxidation and the microbiome composition in soil.

Carbon transformations in the environment are extremely important due to observed climate changes. Various types of pollution resulting from human activity are a factor that modifies the occurrence of these natural processes in the environment. One of these pollutants is vanadium, the presence of which is constantly increasing in the environment. For this reason, the aim of the study was to investigate the influence of vanadium (the most toxic form, pentavalent) on the efficiency of methane oxidation in Leptosol soil. Our research allowed us to identify methanotrophs of the genera Methylobacter and Methylomicrobium in the soil. The presence of these methanotrophs was negatively correlated with the doses of vanadium tested. A decrease in Methylobacter abundance was observed with increased vanadium doses of 188 and 500 mg kg^-1, which was reflected in the methanotrophic activity. A decrease in Methylomicrobium abundance was observed starting from the lower vanadium dose (18.39 mg kg^-1). The presence of both genera was positively correlated with methanotrophic activity, suggesting that both genera may be involved in methane oxidation in this soil. Our research also indicated the genera of microorganisms whose presence was stimulated by the addition of vanadium, including: Nocardioides, Rubrobacter, Bacillus, Paenibacillus, Streptomyces, which indicates that they have defense mechanisms against vanadium and may participate in lowering its concentration in the environment. There were also those whose presence was clearly reduced, such as Acidobacter, Pseudomonas, Hassallia, Gemmatimonas, Methylotenera. This research provides new insight into how vanadium contamination regulates the methanotrophy process in the soil environment.