Properties of antimicrobial substances produced by Bacillus species isolated from rice straw

Abstract

Two hundred bacilli were isolated from rice straw, and 3 strains showing strong inhibitory activities against Bacillus cereus ATCC14579 were selected for further analyses. RSC15 was identified as B. licheni-forms, and RSC26 and RSC42 were identified as B. amyloliquefaciens by molecular identification methods. The inhibitory activities were heat stable, and half of the activity was retained for 20 min at 100 °C. SDS-PAGE analyses of the culture supernatant indicated that 2 different kinds of antibacterial substances were present with sizes below 3.5 kDa. Antibacterial substances produced by B. licheniformis RSC15 were partially purified by column chromatography, and the specific activity increased from 955.0 AU/mg to 6,400 AU/mg. ? 2017, The Korean Society for Microbiology and Biotechnology.