Streptomyces violaceoruber phospholipase A2: expression in Pichia pastoris, properties, and application in oil degumming.

The phospholipase A2 (PLA2) from Streptomyces violaceoruber was successfully expressed in the methylotrophic yeast Pichia pastoris GS115 under the control of AOX1 promoter for the first time. The maximum activity of the recombinant PLA2 (rPLA2) reached 34.7 ± 0.2 U/mL, and specific activity was 170 ± 4 U/mg after purification. On the sodium dodecyl sulfate polyacrylamide gel electrophoresis of the culture supernatants, three bands of 21, 18, and 14.3 kDa were observed. The peptide mass fingerprinting analysis showed that all of these three bands were rPLA2 from S. violaceoruber. By the treatment with Endo H and PNGase F, it indicated that the rPLA2 occurred N-glycosylation. The enzymatic properties of this enzyme were determined. The rPLA2 exhibited a lower optimum pH (pH = 6.0) compared to the wild-type enzyme, which was a desirable property in the application of oil degumming. In the enzymatic degumming process, the phosphorus content decreased from 261.77 ± 3.51 mg/kg to 20.74 ± 0.23 mg/kg, which is very promising for the industrial application.