Polycladomyces zharkentensis sp. nov., a novel thermophilic cellulose-and starch-degrading member of the Bacillota from a geothermal aquifer in Kazakhstan
Mashzhan A. Kistaubayeva A. Javier-López R. Bissenova U. Bissenbay A. Birkeland N.-K.
1 February 2024Microbiology Society
International Journal of Systematic and Evolutionary Microbiology
2024#74Issue 2
A thermophilic, aerobic and heterotrophic filamentous bacterium, designated strain ZKZ2T, was isolated from a pipeline producing hydrothermal water originating from a >2.3 km deep subsurface geothermal source in Zharkent, Almaty region, Kazakhstan. The isolate was Gram-stain-positive, non-motile, heat-resistant and capable of producing a variety of extracellular hydrolases. Growth occurred at temperatures between 55 and 75°C, with an optimum around 70°C, and at pH values between 5.5 and 9.0, with an optimum at pH 7.0–7.5 with the formation of aerial mycelia; endospores were produced along the aerial mycelium. The isolate was able to utilize the following substrates for growth: glycerol, l-arabinose, ribose, d-xylose, d-glucose, d-fructose, d-mannose, rhamnose, d-mannitol, methyl-d-glucopyranoside, aesculin, salicin, cellobiose, maltose, melibiose, sucrose, trehalose, melezitose, raffinose, starch, turanose and 5-keto-gluconate. Furthermore, it was able to hydrolyse carboxymethylcellulose, starch, skimmed milk, Tween 60 and Tween 80. The major cellular fatty acids were iso-C15: 0, iso-C17: 0, iso-C16: 0 and C16: 0. Our 16S rRNA gene sequence analysis placed ZKZ2T within the genus Polyclad-omyces, family Thermoactinomycetaceae, with the highest similarity to the type species Polycladomyces abyssicola JIR-001T (99.18% sequence identity). Our draft genome sequence analysis revealed a genome size of 3.3 Mbp with a G+C value of 52.5 mol%. The orthologous average nucleotide identity value as compared to that of its closest relative, P. abyssicola JIR-001T, was 90.23%, with an in silico DNA–DNA hybridization value of 40.7%, indicating that ZKZ2T represents a separate genome species. Based on the phenotypic and genome sequence differences from the other two Polycladomyces species, we propose that strain ZKZ2T represents a novel species, for which we propose the name Polycladomyces zharkentensis sp. nov. The type strain is ZKZ2T (=CECT 30708T=KCTC 43421T).
geothermal spring in Kazakhstan , Polycladomyces zharkentensis , thermophilic filamentous bacterium
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Department of Biotechnology, Al-Farabi Kazakh National University, Al-Farabi Av. 71, Almaty, 050040, Kazakhstan
Department of Biological Sciences, University of Bergen, P.O. Box 7803, Bergen, NO-5020, Norway
Science Research Institute of Problem Biotechnology at the al-Farabi Kazakh National University, Al-Farabi Av. 71, Almaty, 050040, Kazakhstan
Almaty Branch of the National Center for Biotechnology, Central Reference Laboratory, Zhahanger St. 14, Almaty, 050054, Kazakhstan
Department of Botany, E.A. Buketov, Karaganda State University, Universitet St. 28, Karaganda, 100028, Kazakhstan
Department of Biotechnology
Department of Biological Sciences
Science Research Institute of Problem Biotechnology at the al-Farabi Kazakh National University
Almaty Branch of the National Center for Biotechnology
Department of Botany
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