| Abstrak | Infl uence of soybean meal concentration and 20 kinds of L-amino acids in iturin A production. The use of chemical pesticides has caused serious environmental problems and thus the demand for safer pesticides is increasing. One alternative is microbial pesticides that suppress fungal and bacterial of plant pathogens. Bacillus subtilis has been known as producer of lipopeptide antibiotics, like iturin A, plipastatin and surfactin. In this study, iturin A as an antifungal of plan pathogens was produced on varieties of soybean meal concentration; i.e. 8%, 10%, 12%, and 15% using B.subtilis RB14-CS. The result indicates that 8% soybean meal concentration produced the highest of iturin A production ( 2469 mg L-1) compared to the others. Beside the effect of nitrogen source ( soybean), the infl uence of 20 kinds of L-amino acids on an enhancement of iturin A productivity were observed. The examined L-amino acids were L-ala, L-arg, L-asn, L-asp, L-cys, L-glu, L-gln, L-gly, L-his, L-ile, L-leu, L-lys, L-met, L-pro, L-phe, L-ser, L-thr, L tyr, L-trp and L-val. The results show that no one of them could improve the iturin A productivity on soybean meal medium. |
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