Ecological and biochemical properties of thermophilic bacteria taken from the Dachnie hot springs of Kamchatka (Far East, Russia)

In this work, we studied some ecological and biochemical characteristics (cultural, morphological, physiological and biochemical properties, extracellular enzymatic activity, bacterial growth in various ranges of temperatures, pH, NaCl concentrations, resistance to heavy metals) of 14 strains of thermophilic bacteria taken from thermal waters and microbial mats of Kamchatka Dachnie springs. On selective environment the strains formed mostly transparent, beige, white-gray, brown, yellow and pink colonies. It was shown that the isolates were represented most of all by asporogenic, catalase-positive and oxidase-positive, mobile, gram-negative rods of various sizes. Most of the cultures were capable of forming exozymes, especially amylases and proteinases. The strains grew in a wide range of temperatures (35–50°C), pH (5–8), NaCl concentration (1–5%) and were characterized by increased resistance to a number of heavy metals. 4 strains of thermophilic heterotrophic bacteria exhibited multiple multidrug resistance to metals. They were identified and it was shown that the isolates were represented by bacteria of the genus Bacillus sp. (№ 19), Thermus sp. (№ 40), Pseudomonas sp. (№ 15), Rhizobium sp. (№ 125). The strains with high enzymatic activity and increased resistance to pollutants are promising for use in the field of ecology for cleaning contaminated environmental objects.