Surface display expression of Bacillus licheniformis lipase in Escherichia coli using Lpp'OmpA chimera

The lipase from Bacillus licheniformis ATCC14580 was displayed on the cell surface of Escherichia coli using Lpp'OmpA as the anchoring protein. The expressed Lpp'OmpA-lipase fusion protein has a molecular weight of approximately 35 kDa, which was confirmed by SDS-PAGE and western blot analysis. The Lpp'OmpA-lipase fusion protein was located on the cell surface, as determined by immunofluorescence confocal microscopy and flow cytometry. The enzyme activity of the surface-displayed lipase showed clear halo around the colony. The cell surface-displayed lipase showed the highest activity of 248.12 ± 9.42 U/g (lyophilized cell) at the optimal temperature of 37°C and pH 8.0. The enzyme exhibited the highest activity toward the substrate p-nitrophenyl caprylate (C8). These results suggest that E. coli, which displayed the lipase on its surface, could be used as a whole cell biocatalyst.