Identification of heterotrophic phosphate and silica solubilizing bacterial strains isolated from Lake Baikal

Abstract

The taxonomic composition of phosphatase active bacteria in epilithic bio films is more diverse than that of phosphate solubilizing bacteria. CaSiO₃ and phosphate solubilizing bacteria isolated from epilithic biofilms, water and sediments of Lake Baikal can release acid, alcohol and other compounds during the decomposition of sugars, thereby contributing to the destruction of mineral poorly soluble phosphates and CaSiO₃ compounds. Microbial community of epilithic biofilms dominated by opportunistic microorganisms (Buttiauxella, Serratia, Kosakonia, Yersinia, Aeromonas, and Acinetobacter) that can survive in this biotope for a long time showed a high diversity of groups of phosphate and CaSiO₃ solubilizing bacteria. In addition to opportunistic bacteria, we have isolated bacteria of the genera Phytobacter, Serinibacter, Curtobacterium, Exiguobacterium, Paenibacillus, and Bacillus, which are more often found in the soil, plant tissues or the rhizosphere. These bacteria can be the autochthonous microflora of the epilithic biofilms from Lake Baikal. Moreover, bacteria of the genera Bacillus, Paenibacillus and Serratia can transform both organic and inorganic phosphorus compounds. Such species as Exiguobacterium and Serratia can degrade both poorly soluble phosphorus compounds and calcium silicates.