Difference between revisions of "Team:SZU-China"

What 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-benzenol（2-phenylethanol，2-PE） is one of the most important aromatic compounds, and it has delicate and persistent rose aroma. In recent years, many studies have shown that phenylethanol not only has antibacterial activity, but also its derivative phenylethanol has medicinal value. 2-pe is traditionally extracted from roses, but the yields are usually low. Now days, 2-pe is produced mainly through chemical synthesis, which is environmentally unfriendly and produces unwanted byproducts. Therefore, we selected escherichia coli lacking tnaA gene as the engineering bacteria, and over-expressed tyrosine amino transferase (TyrB) under the control of J23100 promoter. Phenylpyruvate decarboxylase (Aro10) and phenylacetaldehyde reductase (PAR) from rose enable phenylalanine to produce phenylpyruvate by transamination. The above products of phenylpyruvate are generated into phenylacetaldehyde by decarboxylation, which then produced into phenylethanol by dehydrogenation to construct 2-pe biosynthesis pathway. Finally, the metabolic pathways and catalytic conditions were optimized to increase the yield of 2-pe significantly.