Characteristics and vegetable oils degumming of recombinant phospholipase B

Phospholipase B from Pseudomonas fluorescens BIT-18 can cleave acyl chains at the sn-1 and sn-2 positions of a phospholipid and has been successfully used to degum vegetable oils in our previous work. This study focused on the heterologous overexpression of phospholipase B (Pf-PLB-P) in Pichia pastoris to investigate its characteristics and application in degumming vegetable oils. After optimizing the fermentation conditions, the maximum achieved enzyme activity was 65 U/ml, which was twice the enzyme activity of wild-strain P. fluorescens BIT-18. Purified Pf-PLB-P was obtained by ammonium sulfate precipitation, anion-exchange chromatography, and gel filtration. The kinetic constants Km and Vmax were determined to be 4.75 mM and 98.67 mmol/(L min), respectively. Pf-PLB-P enzyme activity was detected at 25–55 °C and pH 4.5–9.5, and the temperature range was observed to be slightly broadened than that of the wild type. Based on these characteristics, Pf-PLB-P was also successfully used to degum soybean and peanut oils, whose phosphorus contents decreased from 125.1 mg/kg to 4.96 mg/kg and 96 mg/kg to 3.54 mg/kg, respectively. These results indicate that Pf-PLB-P produced by P. pastoris has potential industrial use.