Diversity and antibacterial activity of actinomycetes from wetland soil

Abstract

Diversity of soil actinomycetes isolated from various regions of a wetland was analysed. The strains were assigned under 11 genera according to their morphological and biochemical characteristics. They are: Nocardia, Pseudonocardia, Streptomyces, Micromonospora, Rhodococcus, Actinosynnema, Nocardiodes, Kitasatospora, Gordona, Intrasporangium and Streptoalloteichus. Around 55% of the identified strains are Nocardioform actinomycetes. Screening for their antibacterial activities revealed that 96% of the isolated strains showed different degrees of inhibition potential against 12 test pathogenic bacteria (including various serotypes of Salmonella, Vibrio cholerae, Bacillus subtilis and Escherichia coli). Of these about 41% of strains showed antagonism towards Bacillus subtilis. The Nocardioform actinomycetes exhibited antibacterial activity against 9 out of 12 test organisms. The least antibacterial potential was exhibited by Gordona, Rhodococcus, Micromonospora and Kitasatospora. The isolated strains differed among themselves in their ability to decompose proteins and amino acids and also in enzyme production potential.