Effects of CaCl2 on viscosity of culture broth, and on activities of enzymes around the 2-oxoglutarate branch, in Bacillus subtilis CGMCC 2108 producing poly-(γ-glutamic acid)

Regulation of poly-γ-glutamic acid production in Bacillus subtilis GXA-28 by potassium

“…The result differs from other metal ions. For example, there were no readily interpretable correlations between Mn 2+ and γ-PGA molecular weight in B. licheniformis ATCC9945A [5], while high concentration of Na + could reduce γ-PGA molecular weight in B. licheniformis WX-02 [6]and Ca 2+ have no effect on γ-PGA molecular weight in B. subtilis CGMCC2108 [4]. These diversities may be due to the differences of strain properties and γ-PGA synthetase system, which need to be further investigated.…”

“…Metallic ions as a component required of culture media, have been proved to play an important role in the cell growth, γ-PGA yield, stereochemical composition 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 4 and molecular weight of γ-PGA producing strain. For example, γ-PGA yield was increased in the presence of Ca 2+ in the B. subtilis CGMCC 2108 [4]. Mn 2+ has an effect on prolonging the viability of cells which lead to the γ-PGA yield increased, and increasing the proportions of D -isomers of γ-PGA in B. licheniformis 9945A [5].…”

Intracellular synthesis of glutamic acid in Bacillus methylotrophicusSK19.001, a glutamate‐independent poly(γ‐glutamic acid)‐producing strain

“…However, the production of γ ‐PGA increased markedly by 42–71% when α ‐KG combined with l ‐glutamine (each 0.025 mol L −1 ), l ‐glutamine (0.05 mol L −1 ) and citric acid (0.05 mol L −1 ) were added to medium M, but succinic acid and α ‐KG showed only small increases in the production of γ ‐PGA (4.3 and 16.9% respectively). These results indicate that there might be a different regulation system on the carbon source during cultivation in SK19.001 and that the high concentration of citric acid, α ‐KG and l ‐glutamine might activate the key enzymes around the 2‐oxoglutarate branch, such as isocitrate dehydrogenase and GDH …”

“…These results indicate that there might be a different regulation system on the carbon source during cultivation in SK19.001 and that the high concentration of citric acid, -KG and L-glutamine might activate the key enzymes around the 2-oxoglutarate branch, such as isocitrate dehydrogenase and GDH. 21,22 Analyses of enzymatic sources of L-glutamate in production of L-PGA by B. methylotrophicus SK19.001 It is presumed that the intracellular L-glutamic acid is derived from -KG from the TCA cycle in B. subtilis. 13,14 Four different pathways for the formation of L-glutamic acid are proposed as follows.…”

Metabolic engineering of Bacillus amyloliquefaciens for poly‐gamma‐glutamic acid (γ‐PGA) overproduction

“…The approaches employed for the enhancement of γ-PGA production has been mainly focused on two aspects: (i) optimization of the fermentation conditions (Bajaj and Singhal, 2009;Huang et al, 2011) and (ii) characterization of the genes involved in γ-PGA production and use of bioengineering methods to improve the γ-PGA yield (Ashiuchi et al, 2006;Scoffone et al, 2013;Zhang et al, 2013). Increasing numbers of studies have focused on the second approach to construct metabolically engineered microorganisms with high γ-PGA productivity.…”