Characterization of potential biocontrol agent Bacillus sp.

Three potential Bacillus sp. strain, KRG, KRT, and LDR from cocopeat was known to have antagonistic activity against fungal pathogen. The antagonistic activity represented the potency of three isolates as biocontrol agent. In this study, the growth and extracellular enzyme of three isolates will be characterized and also the selected bacterium was identified based on 16S rRNA. The growth of Bacillus sp. strains were characterized in Potato Dextrose Broth (PDB) with various pH medium and temperature incubation. The three isolates can growth at 30–45 °C, meanwhile KRG can grew up to 50 °C. The optimum temperature growth of LDR was 30–45 °C. All of isolates can grow in medium with pH 5–8 with optimal growth for LDR in pH 7–8. Extracellular enzyme assay showed all isolates can produce amylase, lipase, protease, and gelatinase. Molecular identification showed that selected strain LDR is closed to Bacillus siamensis and has 99.52 % similarity with Bacillus siamensis KCTC 13613 strain PD-A10.