Home – Home – Jornals – Chemistry for Sustainable Development 2022 number 4

Microcystin-producing culture of benthic cyanobacterium Tychonema sp. BBK16 isolated from biofilm fouling of the coastal zone of Lake Baikal is described for the first time. The pink colour of the trichomes and the developed keritomy of the cells indicate belonging to the genus Tychonema . Investigation of the morphology and the fragment of the 16S RNA gene showed the uniqueness of this type of cyanobacteria, the closest relative of the new species being the rheophilic cyanobacterium Tychonema sp. K27 from the karstwater stream. At the phylogenetic tree, together they form a separate clade of benthic attached forms. It is determined that the Baikal strain of Tychonema sp. BBK16 produces microcystin LR and does not synthesize anatoxin, which distinguishes it from the previously described species. This ability was revealed in vitro on media with Baikal bottled water and with wastewater from sewage treatment plant of Vydrino settlement. The addition of purified wastewater to the medium enhances the metabolism of cyanobacteria and results in an increase in the concentration of microcystin LR to 320 μg/g of dry weight. Assimilation of the additional amount of biogenic and organic substances by cyanobacteria has a stimulating effect on their metabolism. Analyzing the emergence of cyanobacteria of Tychonema genus in Lake Baikal, we assume that these bacteria undergo mass development in places of excess intake of nutrients, in particular those of organic origin.