L-2-aminobutyric acid is an unnatural amino acid that has the function of inhibiting the transmission of human nervous information, enhancing the activity of glucose phosphatase and promoting the metabolism of brain cells. At present, L-2-aminobutyric acid synthesis methods include chemical and biological methods. The chemical method involves the use of L-methionine as raw material to form L-2-aminobutyric acid under the action of Raney Ni and to perform the chiral resolving reaction. Biosynthetic methods include enzymatic, fermentation and so on.

Chemical method either organic synthesis or chemical splitting, the cost is relatively high. At present, the biosynthesis of L-2-aminobutyric acid has the advantages of mild reaction conditions, high process efficiency and good stereoselectivity. The industrial application is promising. The following describes a method of producing L-2-aminobutyric acid by IPTG-induced fermentation [1]. The synthesis steps are as follows:

(1) The strain is introduced into a seed tank and cultured at a temperature of 33 °C-37 °C with pH of 6.5-7.5, a dissolved oxygen concentration of 15% or more, and a transplanted OD of 9-25, to obtain mature species.

(2) The mature strain is connected to a fermenter and cultured under the following conditions: deep liquid ventilation fermentation, the final concentration of IPTG 0.1-0.3 mmol / L is reached through microfiltration sterilization or flow technology in the early stage of fermentation (cultured to 15h). The required IPTG was added in 15h. The temperature for fermentation process is divided into two stages; temperature is controlled at 34-37 °C in the early stage of fermentation. When the cells grow to the mid-logarithmic phase, the temperature is adjusted to 30-33 °C.

(3) After the fermentation, the fermented liquid is first sterilized by a ceramic membrane, and then 2-4Kd molecular weight ultrafiltration membrane, and decolorized by activated carbon, adsorbed by 732 ion exchange resin and eluted with ammonia, and concentrated by evaporation to obtain L -2-aminobutyric acid.

The purity of the product by the fermentation method can reach more than 95%, which greatly improves the production capacity and the efficiency of the L-2-aminobutyric acid and can satisfy the large-scale industrial production of L-2-aminobutyric acid.

References:

[1] Cao Huajie, Liu Shuai, etc., a method for producing L-2-aminobutyric acid by fermentation, CN105671098A

Edited by Suzhou Yacoo Science Co., Ltd.