Efficient multi-enzyme-catalyzed CDP-choline production driven by an ATP donor module

Cytidine diphosphate choline (CDP-choline) has been applied for treating acute craniocerebral injury and allowing recovery of consciousness after brain surgery. In this study, an acetate kinase (ACK)/acetyl phosphate system was used to supply ATP and combined with Escherichia coli-overexpressed CMP kinase (CMK), NDP kinase (NDK), choline phosphate cytidylyltransferase (CCT), and choline kinase (CKI) to produce CDP-choline from CMP and choline chloride. Within 1 h, 49 mM CDP-choline was produced, for a molar yield of 89.9 and 68.4 % based on CMP and choline chloride, respectively; the utilization efficiency of energy (UEE) was 79.5 %. Acetyl phosphate, sodium acetate, and CTP inhibited the reaction when the concentration exceeded 18.5, 600, and 30 mM, respectively. This inhibition could be overcome by controlling the rate of acetyl phosphate, CMP addition or using KOH instead of NaOH to regulate the pH in fed-batch transformation. After 24 h, the maximum titer was 124.1 +/- 2.7 mM, the productivity was 5.1 +/- 0.1 mM l(-1) h(-1), the molar yield to CMP and choline chloride were 83.8 and 63.7 %, respectively, and the UEE was 58.2 %. This high yield and productivity of CDP-choline through biocatalysis suggest future application at the industrial scale.