Enhancement of gamma-aminobutyric acid production in Chungkukjang by applying a Bacillus subtilis strain expressing glutamate decarboxylase from Lactobacillus brevis.
For a foreign glutamate decarboxylase (GAD) to be expressed in Bacillus host system, a recombinant DNA (pLip/LbGAD) was constructed by ligating an LbGAD gene from Lactobacillus brevis OPK-3 into Escherichia coli-Bacillus shuttle vector, pLip. The pLip/LbGAD construct was then transformed into Bacillus subtilis. The culture of the transformed Bacillus strain with the pLip/LbGAD construct had higher GAD activity and gamma-aminobutyric acid (GABA) concentration than those of untransformed Bacillus counterpart. In addition, Chungkukjang, a traditional Korean fermented soybean product prepared by the transformed Bacillus subtilis, contained a significantly higher level of GABA than conventional ones. Thus, by introducing a foreign GAD gene, Bacillus strains have been genetically engineered to produce high levels of GAD and GABA.
Park
Ki-Bum
KB
Department of Life Science and Technology, Graduate School, Woosuk University, Jeonju 565-701, Korea.
Oh
Suk-Heung
SH
D001412:Bacillus subtilis / Q000201:enzymology*; D003001:Cloning, Molecular; D005285:Fermentation; D005968:Glutamate Decarboxylase / Q000096:biosynthesis*; D052196:Levilactobacillus brevis / Q000201:enzymology*; D013025:Glycine max; D014170:Transformation, Genetic; D005680:gamma-Aminobutyric Acid / Q000096:biosynthesis*
D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase