High efficient extracellular production of recombinant Streptomyces PMF phospholipase D in Escherichia coli

Abstract Background Currently, Streptomyces is widely used in the preparation of phospholipase D (PLD) with high transphosphatidylation activity. However, the yield of PLD from Streptomyces was low and the culture period was long. Therefore, an efficient and cost-effective method is needed urgently.Results Firstly, PLDs from Streptomyces PMF and Streptomyces racemochromogenes were separately over-expressed in E. coli to compare their transphosphatidylation activity based on the synthesis of phosphatidylserine (PS), and PLDPMF was determined to have higher activity. To further improve PLDPMF synthesis, a secretory expression system suitable for PLDPMF was constructed and optimized with different signal peptides. The highest secretory efficiency was observed when the PLDPMF gene was expressed together with its native signal peptide (Nat) and the signal peptide PelB from E. coli. For the application of recombinant PLD to PS synthesis, the PLD properties were characterized and 30.2 g/L of PS was produced after 24 h of bioconversion when 50 g/L phosphatidylcholine (PC) was added.Conclusions We succeeded in over-expressing PLD from Streptomyces PMF in E. coli with high transphosphatidylation activity and enhanced the yield by secretory expression. The secreted PLD was successfully used in the production of PS. Our work makes the large-scale production of PLD and PS feasible.