Streptomyces lothianensis sp. nov., an Antibiotic-Producing Strain Isolated From the Indian Sundarbans Mangrove Forest.

Strain KLOTTS4A1 was isolated from the soil sediment of the mangrove forest of Lothian Island, Sundarbans, West Bengal, India. The chemotaxonomic and phenotypic characteristics of the strain indicated that the isolate belongs to the genus Streptomyces. 16S rRNA gene analysis revealed that the strain was most closely related to the strains Streptomyces indicus IH32-1 (97.65%), Streptomyces montanus NEAU-C151 (97.52%), Streptomyces chlorus BK125 (97.49%) and Streptomyces mesophilus YC504 (97.45%). After genome sequencing, the G + C content of strain KLOTTS4A1 was 71.03 mol%. The ANI and dDDH values between the strain KLOTTS4A1 and its closest neighbor Streptomyces indicus IH32-1 were as follows: ANIb (84.43%), ANIm (87.59%), OrthoANI (84.57%), and GGDC values of 29.40%. All these values are significantly below the established species delineation thresholds of 70% for dDDH and 95%-96% for ANI. Cell wall composition of strain KLOTTS4A1 showed the presence of ribose, mannose, and arabinose. The cell wall composed of LL-DAP in the peptidoglycan. Principle polar phospholipids are phosphatidylethanolamine, diphosphotidyl glycerol, and phosphatidyl inositol. Strain KLOTTS4A1 was characterized by its predominant fatty acids, including iso-C, anteiso-C, and iso-C. Comprehensive genomic and phenotypic analyses revealed that this strain is distinct from closely related species of the genus Streptomyces. Based on these findings, strain KLOTTS4A1 is proposed as a novel species of the genus Streptomyces, for which the name Streptomyces lothianensis sp. nov. is suggested. The type strain is KLOTTS4A1 ( = MTCC 13769 = NRRL B-65739 = COL-B-01923).