Youchun research team of Tianjin Institute of industrial biotechnology, Chinese Academy of Sciences has made new progress in the synthesis of laminarin in vitro

Laminarobiose is a β - 1,3 glycoside linked reducing disaccharide, which is a high value oligosaccharide with various functions It can be used as a precursor of hyaluronic acid synthesis in pharmaceutical and cosmetic industries, as a germinating agent and natural preservative in agricultural fields; it has a prebiotic effect and can be used as a food additive in food health products industry; in addition, laminarin 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 cost-effective and environment-friendly strategy for the preparation of high value-added functional oligosaccharides The research team of the center for in vitro synthetic biology led by researcher you Chun of Tianjin Institute of industrial biotechnology, Chinese Academy of Sciences, designed an in vitro multi enzyme catalytic system to convert cheap substrate starch and glucose into laminarin in one step The system includes α - glucan phosphorylase (α GP) and laminin biose phosphorylase (LBP), in which α GP transforms starch into high energy phosphorylase (g1p), and LBP catalyzes the synthesis of glucose and g1p; in addition, isoamylase (IA) and 4 are added- The yield of laminarin can be increased by using 4-glucono-transferase (4gt) as two auxiliary enzymes Finally, the yield of laminarin based on starch can be further increased to 91.9% by optimizing the reaction system 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 Figure 1 Pathway design for preparation of laminarin from starch and glucose catalyzed by in vitro multi enzyme system (source: Biotechnology Journal) The key deployment project of Chinese Academy of Sciences (zdrw-zs-2016-3), National Natural Science Foundation of China (21778073), Tianjin Science and technology plan project (15ptcysy00020), Sichuan Science and technology plan project (16zc2954) were obtained ）The research results have been published in the journal Biotechnology Journal (DOI: 10.1002 / Biot 201800493) Sun Shangshang, a doctoral student of Tianjin Institute of industrial biology, is the first author of this paper.