High-Yield Phosphatidylserine Production via Yeast Surface Display of Phospholipase D from Streptomyces chromofuscus on Pichia pastoris

The gene encoding phospholipase D (PLD) from Streptomyces chromofuscus was displayed on the cell surface of Pichia pastoris GS115/pKFS-pldh using a Flo1p anchor attachment signal sequence (FS anchor). The displayed PLD (dPLD) showed maximum enzymatic activity at pH 6.0 and 55 degrees C and was stable within a broad range of temperatures (20-65 degrees C) and pHs (pH 4.0-11.0). In addition, the thermostability, acid stability and organic solvent tolerance of the dPLD were significantly enhanced compared with the secreted PLD (sPLD) from S. chromofuscus. Use of dPLD for conversion of phosphatidylcholine (PC) and L-serine to phosphatidylserine (PS) showed that 67.5% of PC was converted into PS at the optimum conditions. Moreover, the conversion rate of PS remained above 50% after 7 repeated batch cycles. Thus, P. pastoris GS115/pKFS-pldh shows the potential for viable industrial production of PS.