ИСТИНА

Lichens are symbiotic systems, which include ascomycete fungi and photosynthetic algae and cyanobacteria as main components. In addition to them, bacteria are the inhabitants of the thalli, and their function in the lichen symbiosis has been little studied. Previously, among already isolated and identified bacteria, strains possessing antibiotic activity, synthesizing indolylacetic acid and chitinases were discovered. In this work, 24 species of lichens were analyzed using FISH and cultivation methods. Alphaproteobacteria class was recognized as the most representative. Among yeasts the most usual were Candida and Dothiora species. From the lichen Ramalina pollinaria, two strains of bacteria phylogenetically close (92% distance) to representatives of the families Beijerinckiaceae and Methylobacteriaceae were isolated and characterized. Strains RmlP001 and RmlP026 are heterotrophs, preferring galactose, lactose, mannitol, glucose, acetylglucosamine as a carbon source, and amino acids as the best source of nitrogen. Representatives of the new family able to accumulate biotechnologically significant amounts of coenzyme Q10, beta-carotene and zeaxanthin. Ecological importance of new bacteria in protecting thalli from high sun exposure and oxidative stress may be assumed. Strain Y-5978 of yeast, close to Phaffia rhodozima (92% distance) was isolated from Cladonia spp. The strain is able to produce carotenoid pigments in quantities that are promising for use in biotech industry. 28 strains from lichens were able to produce significant amounts of extracellular polysaccharides, including bacterial cellulose (strains of Gluconoacetobacter spp.). Probably, bacterial polysaccharides may participate in maintaining the strength and integrity of lichen bodies.