New progress in synthesis of laminarin in vitro

Laminarobiose is a reducing disaccharide linked by β - 1,3 glycoside bond, which is a high value oligosaccharide with various functions It can be used as the precursor of hyaluronic acid synthesis in the pharmaceutical and cosmetics industry, as a germinating agent and natural preservative in the agricultural field, and it has a prebiotic effect, can be used as a food additive in the food health products industry, in addition, it can also regulate the protein expression of Clostridium thermophilus The traditional preparation method of laminarin is to hydrolyze natural products with dilute acid, but the supply of natural products is limited, resulting in the high price of laminarin Therefore, it is of great significance to develop a low-cost and environmentally friendly high-efficiency synthesis technology for the biological preparation of high value-added functional oligosaccharides The research team of the center for in vitro synthetic biology led by you Chun, researcher of Tianjin Institute of industrial biotechnology, Chinese Academy of Sciences, designed an in vitro multi enzyme catalytic system for the one-step conversion of cheap substrate starch and glucose into laminarin The system consists of α - glucan phosphorylase (α GP) and laminarobiose phosphorylase, LBP), in which α GP transforms starch into high-energy phosphorylated sugar (glucose-1-phosphate, g1p), LBP catalyzes the synthesis of laminarin by glucose and g1p; in addition, adding two auxiliary enzymes, isoamylase (IA) and 4-glucantransferase (4gt), can improve the yield of laminarin; finally, through the optimization of the reaction system, starch based laminarin The yield was further increased to 91.9% In order to verify the industrial potential of the reaction path, the research team increased the concentration of substrate starch and glucose, and finally obtained 61.2 g / L of laminarin This new enzyme system can be a platform for the production of disaccharides in the future Different disaccharides can be synthesized by replacing glycoside phosphorylase, which lays a foundation for the production of other disaccharides with starch as substrate.