Antagonist effect of Bacillus spp. against Aspergillus niger CP isolated from cocopeat powder

Abstract

Bacillus spp. are known as potential bacteria as biocontrol agent against fungal phytopathogen, such as Aspergillus niger. The Aspergillus niger can cause many problems, including in agriculture sector. Antagonist activity of 3 bacteria isolates Bacillus sp. KRG, KRT and LDR have been carried out against Aspergillus niger CP. Dual culture method for antagonist assay was performed using streak, disc, and pour plate technique. Result from the disc technique showed that there is no significant antagonist activity differences between all isolates KRG, KRT, and LDR (51.94 %, 61.24 %, and 54.53 %). The highest inhibition effect was shown clearly in pour plate technique with inhibition value almost 100 %. The LDR isolate was selected for further evaluation based on the physicochemical characters according to strong catalase activity and rapid fermentation. Antibiosis assay was performed in order to evaluate the antifungal compound produced by LDR isolate using agar and broth culture method. The filtrates from growth medium 7, 10 and 12 days fermentation were used for antibiosis assay against Asp. niger CP. The growth of Asp. niger CP was inhibited by 10- and 12-days filtrate fermentation in all the 2 methods used. The percentage of inhibition of isolates observed in agar culture were 84.41 % and 84.21 %. Biomass of Asp. niger CP reduced by 74.55 % and 85.54 %.