Isolation and characterization of the novel oil-degrading strain Kosakonia cowanii IUMR B67 and expression of the degradation enzyme

Oils in food waste can pollute the environment and negatively affect human health. Biodegradation is a promising method for disposing of waste edible oils. In this study, an oil-degrading bacterium was isolated from kitchen waste for efficient degradation of edible oils. Its growth and oil degradation characteristics were investigated in basic salt medium with edible oils as the sole carbon and energy source; the triacylglycerol lipase gene (EC 3.1.1.3) was cloned and expressed in Escherichia coli. A novel oil-degrading bacterium assigned as IUMR B67 was successfully isolated. Morphological and molecular analyses revealed that strain IUMR B67 belongs to Kosakonia cowanii. After 144 h of incubation, the oil degradation rate at 37°C was 95.80%. Optimal conditions for IUMR B67 were recorded at 37°C and 0.1% NaCl with 0.1% ammonium sulfate supplementation. The lipase gene of strain IUMR B67 was determined to be 912 base pairs, and the lipase activity of the expressed protein was 3.02 U/mL, which was significantly higher than the control (P < 0.05). Overall, Kosakonia cowanii IUMR B67 is a novel edible oil-degrading strain that can hydrolyze oil via its lipase activity, which may be useful in the disposal of oils and oily food waste.