Abstract: A full-length α-galactosidase gene (melA) sharing 99.2% identity with that previously reported melA (accession number: AF189765) was amplified by polymerase chain reaction (PCR) from L. plantarum 1.557 The PCR-amplified melA gene was cloned into the E. coli-L. plantarum shuttle vector pMG36e and transformed into E. coli DH5α. After the transformant was identified, the recombinant plasmid was purified and electrotransformed into L. lactis. The transformant containing melA gene was easy to detect by the observation of yellow colonies in BCP medium containing melibiose. This result indicated that α-galactosidase gene could be used as a maker for food grade selection.

Key words: α-galactosidase, melA gene, food grade selection marker, shuttle expression vector, Lactococcus lactis