Construction and secretory expression of beta-galactosidase gene from Lactobacillus bulgaricus in Lactococcus lactis.

This study is to examine the secretion effects of beta-galactosidase in Lactococcus lactis. The usp45 and beta-galactosidase genes were cloned and inserted into plasmid pMG36e to obtain the recombinant plasmid pMG36e-usp-lacZ. This recombinant plasmid was transformed into both Escherichia coli DH5alpha and L. lactis MG1363. The enzyme activity, gene sequencing, SDS-PAGE and hereditary stability were assessed and studied. The lacZ gene inserted into plasmids pMG36e-usp-lacZ was 99.37% similar to the GenBank sequence, and SDS-PAGE revealed an evident idio-strap at 116 KDa between L. lactis MG1363/pMG36e-usp-lacZ in both supernatant and cell samples. Beta-Galactosidase activity measured 0.225 U/mL in L. lactis pMG36e-usp-lacZ transformants, and its secretion rate was 10%. The plasmid pMG36e-usp-lacZ appeared more stable in MG1363. The authors concluded that these new recombinant bacteria well expressed and secreted beta-galactosidase, indicating that the beta-galactosidase expression system was successfully constructed, and this might provide a new solution for management of lactose intolerance specifically and promote the use of gene-modified organisms as part of the food-grade plasmid in general.

Citation

Wen Zhang, Chuan Wang, Cheng Yu Huang, Qian Yu, Heng Chuan Liu, Chao Wu Zhang, Xiao Fang Pei. Construction and secretory expression of beta-galactosidase gene from Lactobacillus bulgaricus in Lactococcus lactis. Biomedical and environmental sciences : BES. 2012 Apr;25(2):203-9

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PMID: 22998828

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