Cloning and Heterologous Expression of the β-Galactosidase Gene from Bifidobacterium longum RD47 in B. bifidum BGN4

• Published in: Journal of microbiology and biotechnology pp. 1717 - 1728
• Main Authors: 박민주, 박명수, 지근억
• Format: Journal Article
• Language: English
• Published: 한국미생물·생명공학회 01.11.2019
• Subjects: 생물학
• ISSN: 1017-7825
• DOI: 10.4014/jmb.1812.12002

The gene encoding β-galactosidase was cloned from Bifidobacterium longum RD47 with combinations of several bifidobacterial promoters, and expressed in B. bifidum BGN4. Among the recombinant bifidobacteria, BGN4+G1 showed the highest β-galactosidase level, for which the hydrolytic activity was continuously 2.5 to 4.2 times higher than that of BGN4 and 4.3 to 9.6 times higher than that of RD47. The β-galactosidase activity of BGN4+G1 was exceedingly superior to that of any of the other 35 lactic acid bacteria. When commercial whole milk and BGN4+G1 were reacted, BGN4+G1 removed nearly 50% of the lactose in the milk by the 63-h time point, and a final 61% at 93 h. These figures are about twice the lactose removal rate of conventional fermented milk. As for the reaction of commercial whole milk and crude enzyme extract from BGN4+G1, the β-galactosidase of BGN4+G1 eliminated 51% of the lactose in milk in 2 h. As shown below, we also compared the strengths and characteristics of the strong bifidobacterial promoters reported by previous studies. KCI Citation Count: 0