Characterization of A Lipopeptide Surfactant From Lipase-Producing Bacillus amyloliquefaciens E1PA and Its Role in Lipase-Catalyzed Oil Hydrolysis

Abstract

The lipase-catalyzed hydrolysis of fat and oil is well recognized and considered to be an important reaction in fatty acid production. Generally, lipase activity is poor in oil-water biphasic systems. In this study, surfactins were purified, identified, and molecularly characterized from 2 biosurfactant-producing strains (Bacillus amyloliquefaciens E1PA and B. subtilis TISTR 1248). A high surfactin yield was achieved from B. amyloliquefaciens E1PA culture when 4 % (v/v) glycerol was used as a carbon source. Moreover, the addition of 2 % palm oil to the fermentation broth significantly increased biosurfactant production 2-fold during culture in Mineral Salt Medium (MSM). The biosurfactant synthesized by both strains was partially categorized as a lipopeptide via Fourier transform infrared spectroscopy (FTIR) analysis. The E1PA biosurfactant was subjected to analysis of its interfacial activation in the hydrolysis reaction. The poor hydrolytic activity (12.4 %) of lipase was significantly increased (97.3 %) when surfactin (1 % v/v) was used to generate the emulsion. In addition, the gene involved in B. amyloliquefaciens E1PA surfactin biosynthesis was characterized. The surfactin (sfp) gene was PCR amplified, and then cloning and expression of recombinant sfp was performed in Escherichia coli. Thus, heterogeneous expression of sfp gene in E. coli may be used for the efficient production of active recombinant E1PA surfactin. These results suggest that the lipopeptide biosurfactant produced by B. amyloliquefaciens E1PA could be useful as a biosurfactant in the oleochemical industry to produce fatty acids and/or fatty acid ethyl esters (biodiesel)