Effect of pgsE expression on the molecular weight of poly(γ-glutamic acid) in fermentative production


Poly(γ-glutamic acid) (PGA) is a biopolymer produced by Bacillus spp. via the γ-amide linkages of d- and/or l-glutamate. Although high-molecular-weight (HMW) PGA possesses many attractive properties, such as flocculating, wound healing, and immune-stimulating effects, no studies have reported factors useful for increasing the molecular weight of PGA during microbial production. PgsB, PgsC, and PgsA are the minimum protein sets required for PGA production in B. subtilis, and PgsE improves PGA productivity. Analysis by size-exclusion chromatography combined with multiangle laser light scattering revealed that the molecular weight of PGA was Mw = 2,900,000 g mol−1 and predominantly Mw = 47,000 g mol−1 in preparations derived from B. subtilis cells with and without pgsE, respectively. PgsE may be required to increase the molecular weight of PGA.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1
Fig. 2


  1. 1.

    Ogunleye A, Bhat A, Irorere VU, Hill D, Williams C, Radecka I. Poly-γ-glutamic acid: production, properties and applications. Microbiology. 2015;161:1–17.

    CAS  Article  Google Scholar 

  2. 2.

    Ashiuchi M, Yamashiro D, Yamamoto K. Bacillus subtilis EdmS (formerly PgsE) participates in the maintenance of episomes. Plasmid. 2013;70:209–15.

    CAS  Article  Google Scholar 

  3. 3.

    Taniguchi M, Kato K, Shimauchi A, Ping X, Nakayama H, Fujita K, et al. Proposals for wastewater treatment by applying flocculating activity of cross-linked poly-γ-glutamic acid. J Biosci Bioeng. 2005;99:245–51.

    CAS  Article  Google Scholar 

  4. 4.

    Bajaj I, Singhal R. Poly (glutamic acid)—an emerging biopolymer of commercial interest. Bioresour Technol. 2011;102:5551–61.

    CAS  Article  Google Scholar 

  5. 5.

    Poo H, Park C, Kwak MS, Choi DY, Hong SP, Lee IH, et al. New biological functions and applications of high-molecular-mass poly-γ-glutamic acid. Chem Biodivers. 2010;7:1555–62.

    CAS  Article  Google Scholar 

  6. 6.

    Zhao C, Zhang Y, Wei X, Hu Z, Zhu F, Xu L, et al. Production of ultra-high molecular weight poly-γ-glutamic acid with Bacillus licheniformis P-104 and characterization of its flocculation properties. Appl Biochem Biotechnol. 2013;170:562–72.

    CAS  Article  Google Scholar 

  7. 7.

    Choi JC, Uyama H, Lee CH, Sung MH. Promotion effects of ultra-high molecular weight poly-γ-glutamic acid on wound healing. J Microbiol Biotechnol. 2015;25:941–5.

    CAS  Article  Google Scholar 

  8. 8.

    Yao J, Jing J, Xu H, Liang J, Wu Q, Feng X, et al. Investigation on enzymatic degradation of γ-polyglutamic acid from Bacillus subtilis NX-2. J Mol Catal B Enzym. 2009;56:158–64.

    CAS  Article  Google Scholar 

  9. 9.

    Sung MH, Park C, Kim CJ, Poo H, Soda K, Ashiuchi M. Natural and edible biopolymer poly-γ-glutamic acid: synthesis, production, and applications. Chem Rec. 2005;5:352–66.

    CAS  Article  Google Scholar 

  10. 10.

    Candela T, Mock M, Fouet A. CapE, a 47-amino-acid peptide, is necessary for Bacillus anthracis polyglutamate capsule synthesis. J Bacteriol. 2005;187:7765–72.

    CAS  Article  Google Scholar 

  11. 11.

    Yamashiro D, Yoshioka M, Ashiuchi M. Bacillus subtilis pgsE (Formerly ywtC) stimulates poly-γ-glutamate production in the presence of zinc. Biotechnol Bioeng. 2011;108:226–30.

    CAS  Article  Google Scholar 

  12. 12.

    Kubota H, Matsunobu T, Uotani K, Takabe H, Satoh A, Tanaka T, et al. Production of poly(γ-glutamic acid) by Bacillus subtilis F-2-01. Biosci Biotech Biochem. 1993;57:1212–3.

    CAS  Article  Google Scholar 

  13. 13.

    Orrego C, Arnaud M, Halvorsen HO. Bacillus subtilis 168 Genetic transformation mediated by outgrowing spores: necessity for cell contact. J Bacteriol. 1978;134:973–81.

    CAS  Article  Google Scholar 

  14. 14.

    Ashikaga S, Nanamiya H, Ohashi Y, Kawamura F. Natural genetic competence in Bacillus subtilis natto OK2. J Bacteriol. 2000;182:2411–5.

    CAS  Article  Google Scholar 

  15. 15.

    Irurzun I, Bou JJ, Pérez-Camero G, Abad C, Campos A, Muñoz-Guerra S. Mark-Houwink parameters of biosynthetic poly(γ-glutamic acid) in aqueous solution. Macromol Chem Phys. 2001;202:3253–6.

    CAS  Article  Google Scholar 

  16. 16.

    Suzuki S, Christensen BE, Kitamura S. Effect of mannuronate content and molecular weight of alginates on intestinal immunological activity through Peyer’s patch cells of C3H/HeJ mice. Carbohydr Polym. 2011;83:629–34.

    CAS  Article  Google Scholar 

  17. 17.

    Urushibata Y, Tokuyama S, Tahara Y. Difference in transcription levels of cap genes for γ-polyglutamic acid production between Bacillus subtilis IFO 16449 and Marburg 168. J Biosci Bioeng. 2002;93:252–4.

    CAS  Article  Google Scholar 

  18. 18.

    Bhilocha S, Amin R, Pandya M, Yuan H, Tank M, LoBello J, et al. Agarose and polyacrylamide gel electrophoresis methods for molecular mass analysis of 5–500 kDa hyaluronan. Anal Biochem. 2011;417:41–49.

    CAS  Article  Google Scholar 

  19. 19.

    Ashiuchi M, Soda K, Misono H. A poly-γ-glutamate synthetic system of Bacillus subtilis IFO 3336: gene cloning and biochemical analysis of poly-γ-glutamate produced by Escherichia coli clone cells. Biochem Biophys Res Commun. 1999;263:6–12.

    CAS  Article  Google Scholar 

  20. 20.

    Santelli E, Leone M, Li C, Fukushima T, Preece NE, Olson AJ, et al. Structural analysis of Siah1-Siah-interacting protein interactions and insights into the assembly of an E3 ligase multiprotein complex. J Biol Chem. 2005;280:34278–87.

    CAS  Article  Google Scholar 

Download references


This study was supported in part by the Osaka City University (OCU) Strategic Research Grant 2014 for exploratory research. We are grateful to Kousuke Shinoda for performing the experiments involving E. coli at an early stage of the study; Shou Komaki, Akane Kurita, Ayaka Fujii, and Nanako Iwamoto for technical assistance; Mizuki Taniwa and Saya Yamano for performing the additional experiments against revision; and the Research Center for Bioscience and Technology, Tottori University for amino acid analysis.

Author information



Corresponding author

Correspondence to Ken-Ichi Fujita.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Fujita, KI., Tomiyama, T., Inoi, T. et al. Effect of pgsE expression on the molecular weight of poly(γ-glutamic acid) in fermentative production. Polym J 53, 409–414 (2021). https://doi.org/10.1038/s41428-020-00413-7

Download citation


Quick links