Characterization of An Actinomycete Strain with Bioactivity against Vibrio parahaemolyticus Causing Disease on Shrimp

Abstract

     An experiment was conducted to screen and identify the actinomycete trains that are capable of antagonizing Vibrio parahaemolyticus causing disease on shrimp. Among of 96 isolated strains, three strains were obtained as capable of antagonizing Vibrio parahaemolyticus by agar diffusion plate method. The strain number 25.2 had strongest activity with a diameter of 15 mm clear zone of bacteria. The 25.2 strain showed white colonies but white colonies with grey borders after three and seven days of incubation, respectively. The strain did not produce soluble pigments on Gause-1 medium but grew well at temperatures between 30 - 45°C and neutral pH, and was tolerant to high salt concentration medium. The 25.2 strain was able to utilize several sources of carbon and nitrogen. Results of 16S rRNA sequence analysis showed that the strain 25.2 had a similarity of 96% compared with Streptomyces aureofaciens. Based on morphological characteristics, culture, physiological and biochemical characteristics and molecular biological analyses, the strain 25.2 was identified as Streptomyces aureofaciens.