Search for bacteria capable of biodegradation of microcystins in Lake Baikal using molecular-biological technologies

In aquatic ecosystems, biodegradation of microcystins is the main route of elimination and detoxification. In this study, we discuss the ability of bacterioplankton of lakes Baikal, Doroninskoye, Gusinoye to degrade cyclic microcystin molecule. PCR analysis showed the absence of the key enzyme microcystinase mlrA for mlr-pathway. At the same time, metagenomic analysis of a community of the toxic cyanobacterium Tychonema sp. BBK16 revealed the presence of the mrlC gene responsible for cleavage of microcystin molecule linear residues. In addition, all bacteria-symbionts of cyanobacteria contain glutathione transferases - enzymes involved in nonspecific degradation of lipophilic toxic substances, which also include microcystins.