High-Level Production of Bacteriotoxic Phospholipase Al in Bacterial Host Pseudomonas fluorescens via ABC Transporter-Mediated Secretion and Inducible Expression

Abstract

Bacterial phospholipase A1 (PLA1) is used in various industrial fields because it can catalyze the hydrolysis, esterification, and transesterification of phospholipids to their functional derivatives. It also has a role in the degumming process of crude plant oils. However, bacterial expression of the foreign PLA1-encoding gene was generally hampered because intracellularly expressed PLA1 is inherently toxic and damages the phospholipid membrane. In this study, we report that secretion-based production of recombinant P1aA, a bacterial PLA1 gene, or co-expression of P1aS, an accessory gene, minimizes this harmful effect. We were able to achieve high-level P1aA production via secretion-based protein production. Here, T1iD/T1iE/T1iF, an ABC transporter complex of Pseudomonas fluorescens SIK-W1, was used to secrete recombinant proteins to the extracellular medium. In order to control the protein expression with induction, a new strain of P. fluorescens, which had the lac operon repressor gene lad, was constructed and named ZYAI strain. The bacteriotoxic P1aA protein was successfully produced in a bacterial host, with help from ABC transporter-mediated secretion, induction-controlled protein expression, and fermentation. The final protein product is capable of degumming oil efficiently, signifying its application potential.