Streptomyces monashensis sp. nov., a novel mangrove soil actinobacterium from East Malaysia with antioxidative potential

A new Streptomyces species discovered from Sarawak mangrove soil is described, with the proposed name – Streptomyces monashensis sp. nov. (strain MUSC 1J(T)). Taxonomy status of MUSC 1J(T) was determined via polyphasic approach. Phylogenetic and chemotaxonomic properties of strain MUSC 1J(T) were in accordance with those known for genus Streptomyces. Based on phylogenetic analyses, the strains closely related to MUSC 1J(T) were Streptomyces corchorusii DSM 40340(T) (98.7%), Streptomyces olivaceoviridis NBRC 13066(T) (98.7%), Streptomyces canarius NBRC 13431(T) (98.6%) and Streptomyces coacervatus AS-0823(T) (98.4%). Outcomes of DNA–DNA relatedness between strain MUSC 1J(T) and its closely related type strains covered from 19.7 ± 2.8% to 49.1 ± 4.3%. Strain MUSC 1J(T) has genome size of 10,254,857 bp with DNA G + C content of 71 mol%. MUSC 1J(T) extract exhibited strong antioxidative activity up to 83.80 ± 4.80% in the SOD assay, with significant cytotoxic effect against colon cancer cell lines HCT-116 and SW480. Streptomyces monashensis MUSC 1J(T) (=DSM 103626(T) = MCCC 1K03219(T)) could potentially be a producer of novel bioactive metabolites; hence discovery of this new species may be highly significant to the biopharmaceutical industry as it could lead to development of new and useful chemo-preventive drugs.