Efficient production of poly-gamma-glutamic acid by Bacillus subtilis ZJU-7.
A strain with high poly-gamma-glutamic acid (gamma-PGA) production was isolated from fermented bean curd, a traditional Chinese food. The strain was named Bacillus subtilis ZJU-7 according to 16s rDNA sequencing and its taxonomic characters. The culture conditions for gamma-PGA production were evaluated. The most suitable carbon and nitrogen sources were sucrose and tryptone, respectively. Exogenous L-glutamic acid was necessary for gamma-PGA production, and the production of gamma-PGA increased on the addition of L-glutamic acid to the medium. In the medium containing 60 g/L of sucrose, 60 g/L of tryptone, 80 g/L of L-glutamic acid, and 10 g/L of NaCl, the yield of gamma-PGA reached 54.4 g/L after cultivation at 37 degrees C for 24 h, which was the highest gamma-PGA production compared with values reported in the literature. The average molecular mass of gamma-PGA produced was about 1.24 x 106 Daltons. B. subtilis ZJU-7 is genetically stable and can synthesize levan instead of gamma-PGA without the addition of L-glutamic acid to the medium.
Shi
Feng
F
Institute of Bioengineering, Department of Chemical Engineering and Bioengineering, Zhejiang University, Hangzhou 310027, China.
Xu
Zhinan
Z
Cen
Peilin
P
D001412:Bacillus subtilis / Q000378:metabolism*; D003470:Culture Media; D005285:Fermentation; D018698:Glutamic Acid / Q000494:pharmacology; D007218:Industrial Microbiology; D008970:Molecular Weight; D010461:Peptones / Q000494:pharmacology; D011099:Polyglutamic Acid / Q000096:biosynthesis*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D013025:Glycine max / Q000737:chemistry*; D013395:Sucrose / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D003470:Culture Media; D010461:Peptones; D012336:RNA, Ribosomal, 16S; D011099:Polyglutamic Acid; D018698:Glutamic Acid; D012965:Sodium Chloride; D013395:Sucrose; C001830:tryptones