Characterization of novel phospholipase C from Bacillus licheniformis MTCC 7445 and its application in degumming of vegetable oils

A novel microbial phospholipase C (PLC) from Bacillus licheniformis MTCC 7445 was purified to homogeneity by ammonium sulphate fractionation, dialysis, anion exchange chromatography and gel exclusion chromatography. The bacteria growing on vegetable oils secreted significantly high amount of PLC. The enzyme was purified to 23.4-fold with 46% recovery and specific activity 398 U/mg. It exhibited optimum activity at 70°C and pH 10.0. Using diphosphatidylglycerol as substrate the PLC of B. licheniformis MTCC 7445 had a Vmax and Km of 0.68 mM/min and 32 mM, respectively. It hydrolyzed phosphatidylinositol and phosphatidylserine as well as phosphatidylcholine but not other glycerophospholipids. Its activity was enhanced by 113% with Mn2+ and 110% with Mg2+. During degumming of vegetable oils with this enzyme preparation, the phosphorus content of the oil became lower than 4 mg/kg after 5 h of enzyme treatment at 40°C. The novel PLC from B. licheniformis MTCC 7445 is potentially useful for the refining of high quality oils with 95% removal of phospholipids with attractive yield.