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Food Microbiology | Bioactive Compounds or Metabolites: Function and Application
Microbiol. Biotechnol. Lett.
Tae Jin Kim 1, Min Jae Kim 1, Bong Sin Kim 2, Ji Yeon Yoo 1, Yun Ji Kang 1 and Jeong Hwan Kim 1, 3*
1Division of Applied Life Science (BK Four), Graduate School, Gyeongsang National University, Jinju 52828, Korea, 2Environmental Agriculture Research Division, Gyeongnam Agricultural Research and Extension Services, Jinju, Korea, 52733, 3Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea
Correspondence to :
Jeong Hwan Kim, E-mail : firstname.lastname@example.org
γ-Aminobutyric acid (GABA) is a multi-functional compound with broad applications for food industry. GABA producing lactic acid bacteria (LAB) were screened from cabbage kimchi, a Korean traditional fermented vegetable food. One isolate, B737, produced the highest amount of GABA among the 1,000 isolates when culture supernatants were analyzed by TLC. B737 was identified as Levilactobacillus brevis by 16S rRNA gene sequencing. Its glutamate decarboxylase (GAD) gene was cloned by PCR and the nucleotide sequence determined. B737 GAD consisting of 485 amino acids is the largest GAD among GADs reported from LAB so far. gadB from L. brevis B737 was overexpressed in Escherichia. coli BL21(DE3) using pET26b(+). The size of recombinant GAD was 55 kDa by SDS-PAGE. Maximum GAD activity was observed at pH 5 and 40℃ and the activity was dependent on pyridoxal 5’-phosphate. Km and Vmax of recombinant GAD were 6.2 ± 0.06 mM and 0.34 ± 0.002 mM/min, respectively. L. brevis B737 seems useful as a starter for GABA-enriched foods. Its gadB gene could be used for the overproduction of GABA by recombinant DNA technology, and a source for better understanding of the role and activity of LAB GAD.
Keywords: GABA, Levilactobacillus brevis, glutamate decarboxylase, cabbage kimchi
Jeong A Kim, Ji Yeong Park, and Jeong Hwan KimMicrobiol. Biotechnol. Lett. 2021; 49(1): 9-17 https://doi.org/10.48022/mbl.2002.02019
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