The group of WANG Yong at SIBS Institute of Plant Physiology and Ecology succeeded to design a biosynthetic pathway based on 4 modules which were separately optimized and led to good yields of the desired steviosides. The membrane-associated cytochrome P450 enzyme KAH was identified as the rate-limiting step. To relieve this bottleneck, an engineered CYP714A2 from Arabidopsis thaliana replacing KAHn2 significantly improved the yield of steviol to 15.47 mg l-1. Furthermore, by subsequently incorporating the UGT module, 10.03 mg l-1 of rebaudioside A, the major component of native stevia extracts, was successfully produced in shake flask among various kinds of SGs.
CAS news release, September 17, 2015
CAS SIBS Shanghai obtain high yields of stevioside by E coli-based synthetic biology