Isolation of Bacillus subtilis GS-2 Producing γ-PGA from Ghungkukjang Bean Paste and Identification of γ-PGA

Abstract

γ-PGA(poly-γ-glutamic acid) is an unusual anionic polypeptide that is made of D-and L-glutamic acid units connected by amide linkages between α-amino and γ-carboxylic acid groups. γ-PGA has been isolated from many kinds of organisms. Many Bacillus strains produce γ-PGA as a capsular material of an extracellular viscous material. It is safe for eating as a viscosity element of fermented soybean products such as Chungkookjang and Natto. It is biodegradable, edible and nontoxic toward humans and the environment and its molecular weight varies from ten thousand to several hundred thousand depending on the kinds of strains used. Therefore, potential applications of γ-PGA and its derivatives have been of interest in the past few years in a broad range of industrial fields such as food, cosmetics, medicine, water-treatment, etc. In this study, a bacterium, Bacillus subtilis GS-2 isolated from the Korean traditional seasoning food, Chungkookjang could produce a large amount of γ-PGA with high productivity and had a simple nutrient requirement. Based on carbon utilization pattern and partial 16S rRNA sequence analysis, the GS-2 strain was identified as B. subtilis. The determination of purified γ-PGA was confirmed with thin layer chromatography (TLC), high performance liquid chromatography (HPLC), fourier transform infrared (FT-IR) spectra, and 1 H-nuclear magnetic resonance ( 1 H-NMR) spectroscopy.

Evaluation of the fermentation properties of different soybean (Glycine max L.) cultivars

“…It has been reported that the amounts of sugar and AAs produced by microorganisms during soybean fermentation are highly correlated (Gil et al 2016). VSs produced by fermentation are a polyglutamate mixture of levan and protein decomposed from fructan in soybeans (Bang et al 2011). The VS content was higher in DCK than in other cultivars.…”

Research Progress on the effect of Bacillus on flavor substances of Maotai flavor Baijiu

“…Research findings γ-PGA is made from soybeans fermented by Bacillus spp. and is also an ingredient of Japanese traditional food natto (Bang et al, 2011). Douchi is one of the most popular foods in China, because it has a strong Chifalavour (soybean flavor (Sun et al, 2022), a special ammonia odor different from natto).…”

Influences of Culture Medium Components on the Production Poly (γ-Glutamic Acid) by Bacillus subtilis GS-2 Isolated Chungkookjang

“…The isolated GS-2 strain was identified the method suggested by the Bergey' manual and 16S rRNA sequencing was carried out as described in Seo et al (2008). It was identified as B. subtilis GS-2 (Bang et al 2011). …”