Production of a lipopeptide antibiotic, surfactin, by recombinant Bacillus subtilis in solid state fermentation

Production of a lipopeptide antibiotic, surfactin, in solid state fermentation (SSF) on soybean curd residue, Okara, as a solid substrate was carried out using Bacillus subtilis MI113 with a recombinant plasmid pC112, which contains lpa‐14, a gene related to surfactin production cloned at our laboratory from a wild‐type surfactin producer, B. subtilis RB14. The optimal moisture content and temperature for the production of surfactin were 82% and 37°C, respectively. The amount of surfactin produced by MI113 (pC112) was as high as 2.0 g/kg wet weight, which was eight times as high as that of the original B. subtilis RB14 at the optimal temperature for surfactin production, 30°C. Although the stability of the plasmid showed a similar pattern in both SSF and submerged fermentation (SMF), production of surfactin in SSF was 4–5 times more efficient than in SMF. © 1995 John Wiley & Sons, Inc.