Isolation and characterization of Biotechnologically interesting thermophilic microorganisms from hot springs in Georgia

Author: Natia Geliashvili
Co-authors: Nils Kåre Birkeland, Ekaterine Jaiani, Nunuka Mitskewich
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Abstract Thermophilic bacteria are a less studied but considerable group of microorganisms due to their ability to produce industrial enzymes. Thermophiles are organisms found among the Archaea and Eubacteria domains which are adapted to live at high temperature, the optimal growth temperature being between 50 °C and 79 °C. The majority of hots springs in Georgia are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity of thermophilic microbes. Our research aimed to isolate and characterize new thermophilic bacteria and assess their biotechnological properties. Water samples were collected from a hot spring mixture of water and mud in the central Georgia villages Shakshaketi and Agara. Based on our experiments, three novel thermophile bacteria were isolated from Georgian hot springs. According to biochemical and 16S rRNA gene sequence analysis, isolated strains were identified as Fervidobacterium sp., Caloramator australicus and Pseudothermotoga lettingae. Investigation of metabolic properties of isolates revealed biotechnologicaly the most interesting strain, Fervidobacterium sp. with an ability to degrade keratin, which is a a challenege for the current field of biotechnology. The strain was found to be non-sporulating with optimal growth at 75ᵒC. It grew on a wide range of carbon sources, including glucose, lactose, maltose, starch, arabinose, and xylose amongst others. Most important a newly isolated strain of an anaerobic, thermophilic microorganism belonging to the Thermotogae phylum, Fervidobacterium sp. GSH, was assessed for its capability of degrading native chicken feathers. Therefore, the strain was studied profoundly. By following a multi-omics approach, its proteolytic system was explored, in the attempt to isolate new keratinase candidates. As a result, we have cloned and expressed keratinase gene. The performed genomic analyses included a Fervidobacterium phylogenetic tree reconstruction and genomic comparisons of the studied strain with other Fervidobacterium pennivorans strains. Based on our studies we can conclude that a newly isolated strain of an anaerobic, thermophilic microorganism belonging to the Thermotogae phylum, Fervidobacterium sp. GSH, can be considered as a new species with high biotechnological potential for its capability of degrading native chicken feathers.