Cell surface display of Propionibacterium acnes linoleic acid isomerase by Pichia pastoris

Linoleic acid isomerases (LAIs) catalyze the bioconversion of the linoleic acid to conjugated linoleic acids (CLAs). Due to several beneficial nutritional effects of CLA, research on developing biocatalysts and processes for production of CLA is of great interest. The aim of this study was to develop a whole cell biocatalyst based on the Propionibacterium acnes LAI and yeast cell surface display technology. A cell surface display vector (pPDZ) was first constructed using alpha-factor secretion signal sequence and 3'-half of alpha-agglutinin from S. cerevisiae for Pichia pastoris. Next, the P. acnes LAI was subcloned into pPDZ, and the resulting vector, pPDZ-LAI, was electroporated into Pichia pastoris. Immunofluorescence microscopy and flow cytometric analysis confirmed the successful display of P. acnes LAI on P. pastoris cell surface. However, upon display of the P. acnes LAI on P. pastoris cell surface, inactivation of the enzyme occurred may be due to the post-translational glycosylations and conformational changes. This is the first study on the cell surface display of a LAI enzyme and results may be helpful in developing strategies for LAI biocatalyst production.