Rational Design for the Complete Synthesis of Stevioside in .

Stevioside is a secondary metabolite of diterpenoid glycoside production in plants. It has been used as a natural sweetener in various foods because of its high sweetness and low-calorie content. In this study, we constructed a strain for the complete synthesis of stevioside using a metabolic engineering strategy.

Research on the targeted improvement of the yield of a new VB-producing strain, Ensifer adhaerens S305, based on genomic and transcriptomic analysis.

Background: Vitamin B (VB) has a wide range of applications and high economic value. In this study, a new strain with high VB production potential, Ensifer adhaerens S305, was identified in sewage. Because E.

Effect of blocking the haem synthesis pathway and weakening the haem synthesis pathway for sirohaem on the growth of and vitamin B synthesis in Ensifer adhaerens Casida A.

To block and weaken the bacterial branched VB synthetic metabolic pathway, homologous recombination technology was used to knock out the sirohaem synthase gene cysG located in the chromosome and the endogenous A plasmid of the Ensifer adhaerens Casida A strain, and the expression of the uroporphyrinogen III decarboxylase gene hemE was weakened by weak promoter substitution. The growth of the engineered strains and the production of VB and haem were analysed and measured in the engineered strains, aiming to provide a new strategy for enhancement of VB biosynthesis. The results showed that the chromosomal cysG gene knockout strain ΔcysG, endogenous A plasmid cysG gene knockout strain ΔpAcysG and cysG gene double knockout strain ΔcysGΔpAcysG grew normally, with VB yield increases of 19.