Expression of alpha-Galactosidase Gene from Leuconostoc mesenteroides SY1 in Lactobacillus brevis 2.14

Abstract

alpha-Galactosidase gene (aga) from Leuconostoc mesenteroides SYI was expressed in a heterologous host, Lactobacillus brevis 2.14 using an Escherichia coli-Leuconostoc shuttle vector, pSJE. pSJEaga (pSJE carrying aga) was introduced into Lactobacillus brevis 2.14 by electroporation and transformation efficiency was 1.1 x 10(3) per mu g DNA. L. brevis transformants (TFs) showed higher alpha-galactosiclase (alpha-Gal) activities than cells containing pSJE. Transcription levels of aga in L. brevis 2.14 grown on different carbon sources (1%, w/v) were examined by slot blot analysis. Aga transcript levels and alpha-Gal activities were higher in cells grown oil melibiose, raffinose, and galactose than cells oil glucose, sucrose, and fructose. Western blot result showed that L. brevis 2.14 harboring pSJEaga produced much more alpha-Gal when grown on melibiose than on glucose.