Difference between revisions of "Team:FJNU-China"

What do we want to do?

We designed two applications to bring PLA and 2-PE into practice. In order to highlight the role of PLA and 2-PE, broad-spectrum antibacterial and rose-like aroma compound, we add it to solve the internal and external environment.

    Phenyllactic acid（PLA）widely found in kimchi, honey and other foods. It is a new type of natural antibacterial substance and preservative, which can inhibit a series of Gram-negative, positive bacteria and fungi. Besides, PLA has obvious improvement and protection to the cardiovascular system, which has been widely used in the food and pharmaceutical industries.
The process of chemical synthesis of PLA is complex, costly, environmentally unfriendly, and the products are difficult to be separated and purified, while the biosynthesis method produces PLA with low cost, high purity and low pollutant. In our project, d-lactic acid dehydrogenase (Dldh) and phenylalanine transaminase (Tyrb) were efficiently expressed in escherichia coli, besides, glutamate dehydrogenase (GDH) was expressed, for the internal recycling of cofactor NADH. The phenylalanine was converted to phenylpyruvate by the action of an ammonia-transferase (Tyrb), and then dehydrogenated by a lactate dehydrogenase (Dldh) to produce phenyllactic acid. Finally, the metabolic pathway and catalytic conditions were optimized to significantly improve the yield of PLA.

    2-Phenylethanol (2-PE) is one of the most important perfume, which has a rselike quietly elegant, delicate and persistent aroma. In recent years, many studies have shown that phenylethyl alcohol not only has antibacterial activity, but also its phenylethanoid glycoside has medicinal value. 2-PE is traditionally extracted from rose, the yield is typically low . Nowadays, 2-PE is mostly produced by che- mical synthesis, which is environmentally unfriendly and produces unwanted by-products .Therefore, we used the tnaA gene deletion strain of Escherichia coli as an engineering strain, and co-overexpressing the aromatic transaminase from E. coli (TyrB), phenylpyruvate decarboxylase from S. cerevisiae (Aro10) Par the phenyla- cetaldehyde reductase from the rose (Rosa sp.) under the control of the J23100 promoter.
The phenylalanine is converted to phenylpyruvate by transamination, then acetaldehyde is formed by decarboxylation, and finally 2-phenylethyl is produced by dehydrogenation. The 2-PE biosynthetic pathway was constructed, and finally the metabolic pathway and optimization of the catalytic conditions were carried out to significantly increase the yield of 2-PE.