Selection of an Effective Indicator for Rapid Detection of Microorganisms Producing γ-Polyglutamic Acid and Its Biosynthesis Under Submerged Fermentation Conditions Using Bacillus methylotrophicus

Poonam Mishra Chatterjee, Silpi Datta, Deepika Pandey Tiwari, Ritu Raval, Ashok Kumar Dubey

Research output: Contribution to journalArticle

6 Citations (Scopus)


γ-Polyglutamic acid (γ-PGA) is a biosynthetic outcome of glutamic acid polymerization by microbes. In the current study, we have isolated Bacillus methylotrophicus on solid differential media containing methylene blue. This is the first report mentioning the use of methylene blue to distinguish the monomeric and polymeric form of glutamic acid in the liquid medium using UV-Vis spectrophotometer. Our method can simplify the analytical process of γ-PGA confirmation using the aforementioned studies. This screening protocol is sensitive to the detection of γ-PGA quantities as low as 3 μg/mL; thus, the potent producers can be effectively screened. Furthermore, we have carried out process optimization of the present strain for γ-PGA production wherein we could obtain 1.4-fold improvement in the yield with respect to utilization of carbon source and 2.6-fold increase with respect to nitrogen source under submerged fermentation at a shake flask level. We have shown an increase in γ-PGA titer from 1.5 to 36 g/L using mannitol, monosodium glutamate, peptone, and tween 20.

Original languageEnglish
Pages (from-to)270-288
Number of pages19
JournalApplied Biochemistry and Biotechnology
Issue number1
Publication statusPublished - 01-05-2018


All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Bioengineering
  • Biochemistry
  • Applied Microbiology and Biotechnology
  • Molecular Biology

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