Difference between revisions of "Team:Amoy/Project"

• Description
• Background
• Methods
• Results
• Discussion
• Future work

ABSTRACT

L-tert-leucine (Tle) is an important and attractive chiral building block, which can be used to product protease inhibitors of HIV, HCV and so on. Many chemical methods have been used in Tle synthesis, but products are usually racemic. In order to solve the problem, scientists developed enzymatic reductive amination to product Tle by using leucine dehydrogenase (LeuDH) and formate dehydrogenase (FDH) with cofactor-NADH. It greatly improved the yield and optical purity of Tle.

Initially, isolated enzymes are easily destabilized in the isolation and purification process. What's more, NADH is rather an expensive material, which will enhance the cost of Tle production. So scientists introduced Tle production into whole-cell biocatalysts.

However, owing to different activities of LeuDH and FDH, the NADH consumption would be faster than its regeneration. Therefore, addition of excess NADH is necessary. Many methods have been used, but none made difference.

Our project devised a method that regulating the activity of LeuDH by changing RBS of leudh, which is connected with fdh in a plasmid. This idea controls copy numbers and transformation efficiency, and the only variable is RBSs’ efficiency. Finally, we got different gene circuits and found the suitable efficiency of RBS.