Comparison of lipopeptide biosurfactants production by Bacillus subtilis strains in submerged and solid state fermentation systems using a cheap carbon source: Some industrial applications of biosurfactants

Biosurfactants, in general has the potential to aid in the recovery of subsurface organic contaminants (environmental remediation) or crude oils (oil recovery). However, high production and purification costs limit its use in these high-volume applications. In the present study, the efficiency of two Bacillus subtilis strains viz., DM-03 and DM-04 for the production of biosurfactants in two fermentation systems viz., solid state fermentation (SSF) and submerged fermentation (SmF) was compared. Both the B. subtilis strains produced appreciable and equal amount of crude lipopeptide biosurfactants (B. subtilis DM-03: 80.0 ± 9 mg/gds in SmF and 67.0 ± 6 mg/gds in SSF; B. subtilis DM-04: 23.0 ± 5.0 mg/gds in SmF and 20.0 ± 2.5 mg/gds in SSF) in the two different fermentation systems using potato peels as cheap carbon source. These thermostable lipopeptide biosurfactants produced by B. subtilis strains either in SSF or in SmF, exhibited strong emulsifying property and could release appreciable amount of oil from saturated sand pack column. Further, it was shown by biochemical analysis, RP-HPLC profile and IR spectra that there is no qualitative and qualitative differences in the composition of crude biosurfactants produced either in SmF or in SSF system.