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The production of a thermophilic 2-deoxyribose-5-phosphate aldolases (DERA) in Escherichia coli BL21 under continuous lactose induction strategy was investigated. The process was combined with the exponential feeding method, controlling the feeding rate to maintain the specific growth rate at 0.15 h(-1). The results indicate that the lactose concentration in the feed medium affected directly the expression of the target protein. The use of 50 g/L in the feed medium resulted in the biomass concentration of 39.3 g DCW/L, and an expression level of above 30%, and the maximum final DERA concentration of 16,200 U/L. Furthermore, the acetate concentration remained at a low level in the fed-batch phase, less than 0.5 g/L. In conclusion, combining glucose feeding with lactose induction is a more powerful way to achieve high cell density cultures and to efficiently produce the thermophilic DERA. The results also indicate the potential industrial utility in the scale production of other recombinant proteins.

Alkenes are one of the most abundant raw feedstocks to construct complex chemicals, cross-coupling reactions using alkenes provides powerful methods toward valuable chemicals. In the past decade, cross-coupling reaction of simple alkenes by chelation-assisted alkenyl C−H functionalization has attracted many attentions due to its atom- and step efficiency, as well as excellent Z/E selectivity, proceeding by C−H exo-cyclometallation and endo-cyclometallation. In this Account, we would like to summarize transition-metal-catalyzed cross-coupling reactions between alkenes to generate 1,3-dienes by C−H alkenylation,1,4-dienes by C−H allylation, multi-substituted alkenes by hydroalkenylation, and heterocycles by tandem alkenyl C-H functionalization/annulation. Asymmetric alkenyl C−H alkenylation to prepare axially chiral aryl 1,3-dienes was also included.