High‐effective biosynthesis of baccatin Ⅲ by using the alternative acetyl substrate, N‐acetyl‐ d ‐glucosamine

Paclitaxel is a type of broad‐spectrum anticancer drug in short supply. The price of acetyl‐CoA (17 709 677·4 USD mol−1), which is the acetyl group donor for the enzymatic synthesis of the intermediate, baccatin Ⅲ, is still the bottleneck of the mass production of paclitaxel. This study reports a novel acetyl group donor, which could substantially reduce the cost of production. In this study, a substrate spectrum with 14 kinds of representative acetyl‐donor substitutes predicted by computer‐aided methods was tested in a 10‐deacetylbaccatin Ⅲ‐10‐O‐acetyltransferase (DBAT) heterogeneous‐expressed open‐whole‐cell catalytic system. The results of computer prediction and experimental analysis revealed the rule of the acetyl‐donor compounds based on this substrate spectrum. N‐acetyl‐d‐glucosamine (30·95 USD mol−1, about 572 202‐fold cheaper than acetyl‐CoA) is selected as a suitable substitute under the rule. The yield when using N‐acetyl‐d‐glucosamine as acetyl donor in open‐whole‐cell catalytic system was 2·13‐fold of that when using acetyl‐CoA. In the in vivo system, the yield increased 24·17%, which may indicate its cooperation with acetyl‐CoA. The success of open‐whole‐cell synthesis and in vivo synthesis of baccatin Ⅲ by adding N‐acetyl‐d‐glucosamine as acetyl substrate demonstrates that it is a useful substrate to improve the yield of baccatin Ⅲ. All these findings provided a potential acetyl‐donor substitute for acetyl‐CoA, as well as a low cost and efficient method of preparing paclitaxel through baccatin Ⅲ semi‐synthesis.