3-Hydroxypropionic acid production by recombinant Escherichia coli ZJU-3HP01 using glycerol-glucose dual-substrate fermentative strategy.

3-Hydroxypropionic acid (3-HP) is an important platform synthesis block for sets of chemicals, but the relatively low production of 3-HP from biological sources presented major barriers for its industrial applications. In this study, a dual-substrate fermentative strategy by glycerol and glucose was proposed, and the aim was to evaluate the effect of different substrate addition strategies on the fermentation process. The results indicated that the optimal cosubstrate was glucose (20 g/L), and the enzymatic activity of aldehyde dehydrogenase (AldH) could be improved 3.5-fold as compared with no glucose addition. Continuous fed-batch fermentation at a constant speed displayed better 3-HP production of 17.20 g/L and highest specific 3-HP productivity of 1.79 mmol/(g cell·H) than the other fed-batch mode. The addition of glucose could greatly reduce the imbalance of the activity between glycerol dehydratase and AldH and provide a feasible method for improving 3-HP production. These results would be helpful in developing the 3-HP fermentation process.