PDF(Pubmed)
Abstract：
Baccatin III is a crucial precursor in the biosynthesis pathway of paclitaxel. Its main sources are extraction from Taxus or chemical synthesis using 10-deacetylbaccatin III (10-DAB) as substrate. However, these preparation approaches exhibit serious limitations, including the low content of baccatin III in Taxus and the complicated steps of chemical synthesis. Heterologous expression of 10-deacetylbaccatin III-10-O-acetyltransferase (TcDBAT) in microbial strains for biotransformation of 10-DAB is a promising alternative strategy for baccatin III production. Here, the promotion effects of glycerol supply and slightly acidic conditions with a low-temperature on the catalysis of recombinant TcDBAT strain were clarified using 10-DAB as substrate. Taxus needles is renewable and the content of 10-DAB is relatively high, it can be used as an effective source of the catalytic substrate 10-DAB. Baccatin III was synthesized by integrating the extraction of 10-DAB from renewable Taxus needles and in situ whole-cell catalysis in this study. 40 g/L needles were converted into 20.66 mg/L baccatin III by optimizing and establishing a whole-cell catalytic bioprocess. The method used in this study can shorten the production process of Taxus extraction for baccatin III synthesis and provide a reliable strategy for the efficient production of baccatin III by recombinant strains and the improvement of resource utilization rate of Taxus needles.
摘要：
囊素III是紫杉醇生物合成途径中的关键前体。它的主要来源是从红豆杉中提取或以10-脱乙酰浆果蛋白酶III（10-DAB）为底物的化学合成。然而,这些制备方法表现出严重的局限性，包括红豆杉中的baccatinIII含量低和化学合成步骤复杂。在10-DAB生物转化的微生物菌株中异源表达10-脱乙酰浆果蛋白酶III-10-O-乙酰转移酶（TcDBAT）是生产浆果蛋白酶III的有希望的替代策略。这里,以10-DAB为底物，阐明了甘油供应和低温微酸性条件对重组TcDBAT菌株催化的促进作用。紫杉针是可再生的，10-DAB的含量相对较高，它可以用作催化底物10-DAB的有效来源。在这项研究中，通过整合从可再生紫杉树针中提取10-DAB和原位全细胞催化来合成浆果蛋白酶III。通过优化和建立全细胞催化生物过程，将40g/L的针头转化为20.66mg/L的浆果蛋白酶III。本研究所采用的方法可以缩短红豆杉提提取好库赤霉素Ⅲ的生产工艺,为重组菌株高效生产好库赤霉素Ⅲ和提高红豆杉针叶资源利用率提供了可靠的策略。
