Method for improving yield of epsilon-polylysine by low pH value stress

Abstract

The invention discloses a method for improving the yield of epsilon-polylysine by low pH value stress and belongs to the technical field of fermentation engineering. In a fermentation process, an acid pH stress process is introduced, namely the pH is artificially or spontaneously reduced to 2.5-3.0 and is maintained for 12-48 hours; then the pH is improved to 3.5-4.5 and keeps stable until the fermentation is finished. With the adoption of a pH regulating and controlling method, the specific growth rate of epsilon-polylysine producing bacteria and the specific synthesis speed of the epsilon-polylysine can be remarkably improved; a material supplementing-batch fermentation manner is combined so that the yield of the epsilon-polylysine is improved by more than 50% when being compared with that a common two-phase pH regulating and controlling method. According to the method, a low pH stress method is introduced into an epsilon-polylysine fermentation process so that the fermentation level of the epsilon-polylysine is remarkably improved. Furthermore, the method is simple to operate and has remarkable effect so that the implementation of large-scale industrial production is facilitated.

Description

technical field

[0001] The invention relates to a method for increasing the yield of ε-polylysine under low pH value stress, and belongs to the technical field of fermentation engineering. Background technique

[0002] ε-polylysine (ε-poly-L-lysine, ε-PL) is a kind of L-lysine homopolymer synthesized and secreted by microorganisms, which consists of 25-35 L-lysine residues through α- It is polymerized by dehydration condensation of carboxyl group and ε-amino group. ε-PL has the advantages of good water solubility, high thermal stability, edible, degradable and non-toxic to human and environment. In addition, ε-PL also has a broad antibacterial spectrum, and has a good inhibitory effect on Gram-positive bacteria, Gram-negative bacteria, yeast and mold. Therefore, ε-PL, as an excellent biological food preservative, has been approved for use in the food processing industry by Japan, South Korea, the United States, Europe and other countries and regions. In April 2014, my cou...