Production of lipopeptide antibiotic iturin A using soybean curd residue cultivated with Bacillus subtilis in solid-state fermentation.
Bacillus subtilis RB14-CS, which suppresses the growth of various plant pathogens in vitro by producing the lipopeptide antibiotic iturin A, was cultured using soybean curd residue, okara, a by-product of tofu manufacture in solid-state fermentation. After 4 days incubation, iturin A production reached 3,300 mg/kg wet solid material (14 g/kg dry solid material), which is approximately tenfold higher than that in submerged fermentation. When the okara product cultured with RB14-CS was introduced into soil infested with Rhizoctonia solani, which is a causal agent of damping-off of tomato, the disease occurrence was significantly suppressed. After 14 days, the number of RB14-CS cells remained in soil at the initial level, whereas almost no iturin A was detected in soil. As the okara cultured with RB14-CS exhibited functions of both plant disease suppression and nutritional effect on tomato seedlings, this product is expected to contribute to the recycling of the soybean curd residue.
Mizumoto
S
S
Chemical Resources Laboratory, Tokyo Institute of Technology, R1-29-4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.
Hirai
M
M
Shoda
M
M
D001412:Bacillus subtilis / Q000378:metabolism*; D019149:Bioreactors; D005285:Fermentation / Q000502:physiology*; D005308:Fertilizers; D018551:Solanum lycopersicum; D010456:Peptides, Cyclic / Q000096:biosynthesis*; D010940:Plant Proteins / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D045730:Soy Foods
D005308:Fertilizers; D010456:Peptides, Cyclic; D010940:Plant Proteins; D011134:Polysaccharides; C412882:okara, Glycine max; C013579:iturin A