Study on the Stability of Poly-glutamic Acid Fermentation Broth for Agricultural Use

Poly-glutamic acid has been widely recognized in the field of agriculture as well as widely used in the field of medicine and cosmetics. However, because of its high cost and poor liquid stability, it has greatly restricted its application in agriculture. In this paper, poly-glutamic acid fermentation broth produced by Bacillus licheniformis A2-10 was fermented, and the liquid storage temperature, pH, and protective agents were optimized to enhance the stability of poly-glutamic acid fermentation broth. The preservation conditions of poly-glutamic acid are as follows: 20 °C, pH6.5, adding 2% urea, the viscosity of the fermentation liquid can be retained over 70% in 30 days, which is 10.67 times higher than that in the blank.