Taxonomy and antimicrobial activity of moderately salt-tolerant and alkaliphilic Streptomyces sp. MN 9(V) isolated from solitary wasp mud nest

Abstract

An actinobacterium strain designated as MN 9(V) was isolated from solitary wasp mud nest obtained from the walls of buildings located in Dehradun, India. MN 9(V) was subjected to polyphasic taxonomic characterization. The organism produced light-grey aerial mycelium with brown-coloured diffusible pigment. This isolate showed growth in medium containing 8% NaCl, at pH 8–10 and at a temperature range of 27–45°C. Micromorphology and chemotaxonomic characteristics were consistent with its assignment to the genus Streptomyces. Analysis of 16S rDNA gene sequences showed that MN 9(V) formed a separate clade with Streptomyces cellulosae NRRLB-2889T and Streptomyces pseudogriseolus NRRL B-3288T being most closely related with a sequence similarity of 99%. However, a number of phenotypic characteristics readily distinguished the strain MN 9(V) from the type strains. The strain MN 9(V) showed strong antimicrobial activity against several test organisms, including multidrug resistant bacteria, as well as against fungal pathogens.