Abstract:

In order to investigate the function of linoleic acid isomerase( LAI) and construct the recombinant yeast strains,first,the lai gene was cloned from Lactobacillus plantarum lp15-2-1,with its coding sequence being also analyzed. Then,lai was fused to the sequences of both the signal peptide of yeast and the anchor region of α-agglutinin,thus constructing the yeast cell-surface display vector. Finally,the vector was transformed into Saccharomyces cerevisiae K601 by means of the electroporation,and the transformants were screened by using the synthetic dropout medium without uracil. Amino acid sequence analysis shows that LAI is of a high homology to the myosin-cross-reactive antigen proteins as well as of a semi-conserved flavin adenine dinucleotide binding motif near the N-terminus. The activity results of the recombinant yeast strains demonstrate that LAI from Lactobacillus plantarum is successfully displayed on the cell-surface of yeast K601,and that the activity of LAI reaches the maximum 40.5U/mL in 48 h. Moreover,GC results indicate that the recombinant yeast strains are capable of producing a single c9,t11- CLA isomer.

Key words: Lactobacillus plantarum, Saccharomyces cerevisiae, linoleic acid isomerase, surface display, flavin adenine dinucleotide