Relationship between lipopeptide biosurfactant and primary metabolite production by Bacillus strains in solid-state and submerged fermentation.

The relationship between lipopeptide and primary metabolite production by Bacillus spp. in solid-state fermentation (SSF) and submerged fermentation (SmF) was evaluated. Four wild-type strains and one mutant strain (unable to develop biofilm) were assessed in SSF and SmF, using a defined medium and polyurethane foam as inert support for SSF. Strain ATCC 21,332 in SSF presented the highest lipopeptide production. The wild-type strains revealed higher lipopeptide and biomass production and lower synthesis of primary metabolites in SSF than in SmF. However, the mutant strain showed a slightly higher production of primary metabolites in SSF than in SmF. Carbon balance analysis showed that the carbon flux was mainly directed to lipopeptides in SSF, whereas in SmF, it was directed to the production of primary metabolites and the carbon flux to lipopeptides is inversely related to primary metabolites in both types of cultures.