ANTIFUNGAL PRODUCTION OF BACILLUS SIAMENSIS LDR AGAINST ASPERGILLUS NIGER ABP AND ART USING RICE STARCH AS CARBON SOURCEInneke Kusanggraeni, Iman Santoso and Yasman
Problems can be emerged from contaminated food and agricultural products by Aspergillus niger. The growth of A. niger can be managed by biocontrol using antifungal compound produced by fermentation process. Nutrient composition of fermentation medium is one of important factors. In this research, production of antifungal compound from Bacillus siamensis LDR was carried out against two strains of A. niger ABP and ART. Rice starch as carbon source and yeast extract was added into Czapek-Dox medium as a fermentation medium. Fermentation was performed in still culture method within 10, 12, and 14 days. Antibiosis assay was done using filtrate of fermentation medium as solvent for preparing PDB and PDA media. The result was determined based on the biomass growth in PDB and the growth diameter in PDA from A. niger ABP and ART. Antibiosis assay using filtrate of 10 days fermentation showed significant effectivity in biomass reduction of A. niger ABP (99.20%) and growth diameter inhibition (83.28%). Significant effectivity was shown by filtrate of 12 days fermentation which reduced biomass (89.62%) and growth diameter inhibition (87.95%) of A. niger ART. Plate agar antibiosis assay was also done with the crude extract of medium from 12 days fermentation. Filtrate medium was extracted with ethyl acetate using liquid-liquid extraction method. Concentrations of antifungal crude extract were 2,500, 5,000, 10,000, and 20,000 ppm. The inhibition growth of A. niger ABP and ART were already observed at 2,500 ppm.