Abstract
Glycerol would stimulate the production of poly(γ-glutamic acid) (γ-PGA) and decrease its molecular weight in Bacillus subtilis NX-2. When 20 g/l glycerol was added in the medium, the yield of γ-PGA increased from 26.7 ± 1.0 to 31.7 ± 1.3 g/l, and molecular weight of γ-PGA decreased from 2.43 ± 0.07 × 106 to 1.86 ± 0.06 × 106 Da. In addition, it was found that the decrease of γ-PGA chain length by glycerol would lead to the decrease of broth viscosity during the fermentation and enhanced the uptake of substrates, which could not only improve cell growth but also stimulate γ-PGA production. Moreover, it was also found that glycerol could effectively regulate molecular weight between 2.43 ± 0.07 × 106 and 1.42 ± 0.05 × 106 Da with the concentration ranging from 0 to 60 g/l. This was the first time to discover such contribution of glycerol on γ-PGA production in Bacillus genus. And the effects of glycerol on molecular weight of γ-PGA would be developed to be an approach for the regulation of microbial γ-PGA chain length, which is of practical importance for future commercial development of this polymer.
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References
Shih, I. L., & Van, Y. T. (2001). Bioresource Technology, 79, 207–225. doi:10.1016/S0960-8524(01)00074-8.
Birrer, G. A., Cromwick, A., & Gross, R. A. (1994). International Journal of Biological Macromolecules, 16, 265–275. doi:10.1016/0141-8130(94)90032-9.
Cromwick, A. M., & Gross, R. A. (1995). International Journal of Biological Macromolecules, 17, 259–267. doi:10.1016/0141-8130(95)98153-P.
Kunioka, M. (1995). Applied Microbiology and Biotechnology, 44, 501–506. doi:10.1007/BF00169951.
Ko, Y. H., & Gross, R. A. (1998). Biotechnology and Bioengineering, 57, 430–437. doi:10.1002/(SICI)1097-0290(19980220)57:4<430::AID-BIT6>3.0.CO;2-N.
Richard, A., & Margaritis, A. (2003). Biotechnology and Bioengineering, 82, 299–305. doi:10.1002/bit.10568.
Xu, H., Jiang, M., Li, H., Lu, D., & Ouyang, P. (2005). Process Biochem, 40, 519–523. doi:10.1016/j.procbio.2003.09.025.
Wu, Q., Xu, H., Xu, L., & Ouyang, P. (2006). Process Biochem, 41, 1650–1655. doi:10.1016/j.procbio.2006.03.034.
Cromwick, A. M., Birrer, G. A., & Gross, R. A. (1996). Biotechnology and Bioengineering, 50, 222–227. doi:10.1002/(SICI)1097-0290(19960420)50:2<222::AID-BIT10>3.0.CO;2-P.
Ashby, R. D., Solaiman, D. K. Y., & Foglia, T. A. (2005). Biomacromolecules, 6, 2106–2112. doi:10.1021/bm058005h.
Nishikawa, M., & Ogawa, K. (2006). Applied and Environmental Microbiology, 72, 2306–2312. doi:10.1128/AEM.72.4.2306-2312.2006.
Richard, A., & Margaritis, A. (2003). Biotechnology Letters, 25, 465–468. doi:10.1023/A:1022644417429.
Yoon, S. H., Do, J. H., Lee, S. Y., & Chang, H. N. (2000). Biotechnology Letters, 22, 585–588. doi:10.1023/A:1005625026623.
Acknowledgment
This work was supported by the National Basic Research Program of China (973 Program, 2007CB714304), the National High Technology Research and Development Program of China (863 Program, 2006AA03Z453), the National Nature Science Foundation of China (20674038), and the Graduate Student Innovation Project of Jiangsu Province.
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Wu, Q., Xu, H., Liang, J. et al. Contribution of Glycerol on Production of Poly(γ-Glutamic Acid) in Bacillus subtilis NX-2. Appl Biochem Biotechnol 160, 386–392 (2010). https://doi.org/10.1007/s12010-008-8320-2
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DOI: https://doi.org/10.1007/s12010-008-8320-2