Mevalonate is one of the most important intermediate in the biosynthesis of more than 50 thousand kinds of natural terpeniods. Choice of appropriate feedstocks for industrial biotechnology is of importance. Our research objective is to produce terpenoids by engineering the synthesis pathway in methylotrophic cell factories using methanol as the carbon and energy source.
A mevalonate-producing pathway in M.extorquens AM1 as the model host was established by the following three steps. First, the upstream mevalonate pathway was designed and introduced into M.extorquensAM1, and the highest mevalonate titer of 179 mg/L was achieved by an engineered strain of AM1/Mvt. Second, RBS engineering was used for balancing the metabolic flux of upstream mevalonate pathway, and the mevalonate titer was increased by 20%, reaching 215 mg/L. And last, local regulation engineering with the error-prone mutation of QscR, a local regulator of serine cycle in M.extorquens AM1 was explored to control the metabolic flux to mevalonate pathway. For high throughput screening of the engineered strains with high production of mevalonate, an intracellular mevalonate biosensor was constructed and the FACS-based screening method was established.
This microbial cell factory can be applied to produce many other value-added terpenoids by docking with their biosynthesis pathway. It shows great potential value for industrial biotechnology.