Isolation of Bacillus subtilis (chungkookjang), a poly-?-glutamate producer with high genetic competence

Abstract

A bacterium with high poly-gamma-glutamate (PGA) productivity was isolated from the traditional Korean seasoning, Chung-Kook-Jang. This bacterium could be classified as a Bacillus subtilis, but sporulation in culture was infrequent in the absence of Mn2+. It was judged to be a variety of B. subtilis and designated B. subtilis (chungkookjang). L-Glutamate significantly induced PGA production, and highly elongated PGAs were synthesized. The volumetric yield reached 13.5 mg ml(-1) in the presence of 2% L-glutamate. The D-glutamate content was over 50% in every PGA produced under the conditions used. During PGA production, glutamate racemase activity was found in the cells, suggesting that the enzyme is involved in the D-glutamate supply. Molecular sizes of PGAs were changed by the salt concentration in the medium; PGAs with comparatively low molecular masses were produced in culture media containing high concentrations of NaCl. B. subtilis (chungkookjang) harbors no plasmid and is the first B. subtilis strain reported with both naturally high PGA productivity and high genetic competence.

Poly-γ-glutamic acid: production, properties and applications

“…In the case of B. anthracis, the genes involved in c-PGA synthesis lie on a large plasmid, as opposed to other Bacillus species where the genes are present on the chromosome (Ashiuchi et al, 2001a;). …”

“…The L-glutamic-aciddependent bacteria include B. subtilis (chungkookjang) (Ashiuchi et al, 2001a), B. licheniformis 9945a (Birrer et al, 1994) B. subtilis CGMCC 0833 , B. licheniformis NK-03 (Cao et al, 2010) and B. subtilis (natto) ATCC 15245 (Bhat et al, 2013), whilst the non-Lglutamic-acid-dependent producers include B. subtilis C1 (Shih et al, 2005), B. amyloliquefaciens LL3 (Cao et al, 2011) and B. subtilis C10 (Zhang et al, 2012). For Lglutamic-acid-dependent bacteria, the PGA yield increases with an increase in the L-glutamic acid concentration in the medium.…”

Oral Administration of High Molecular Mass Poly-γ-Glutamate Induces NK Cell-Mediated Antitumor Immunity

“…Recently, Bacillus subtilis sups. chungkookjang, isolated from chungkookjang, a traditional Korean fermented soybean food, was reported to produce ␥-PGA, a copolymer of Dand L-glutamate that has a higher molecular mass (Ͼ1000 kDa) than ␥-PGA (10 -10,000 kDa) produced from B. subtilis (natto) (2). Currently, we studied the antitumor effects of the high molecular mass ␥-PGA isolated from B. subtilis (chungkookjang) to determine whether this might be a source for an effective oral antitumoral agent and the basis underlying these effects.…”

Fermented Soybean Products and Their Bioactive Compounds

“…Park et al, 2001) are reported. Anti-obesity effects were reported in mice and rats fed with high fat diets (Ashiuchi et al, 2001;Choo, 2000;Koo et al, 2008); fermented kochujang supplementation of a high fat diet prevented obesity in mice by reducing fat deposition and decreased circulating levels of cholesterol, triglycerides, and blood glucose, mediated by downregulating expression of lipogenic enzymes and up-regulating the lipolytic enzymes and the thermogenesis gene UCP-1 (Koo et al, 2008).…”