Microbial hydrolysis of 7-xylosyl-10-deacetyltaxol to 10-deacetyltaxol

Enterobacter sp. CGMCC 2487, a bacterial strain isolated from the soil around a Taxus cuspidata Sieb. et Zucc. plant, was able to remove the xylosyl group from 7-xylosyltaxanes. The xylosidase of this strain was an inducible enzyme. In the bioconversion of 7-xylosyl-10-deacetyltaxol (7-XDT) to 10-deacetyltaxol (10-DT), for the purpose of enhancing the conversion efficiency, the effects of NH4+, oat xylan, temperature, pH value, cell density and substrate concentration on the bioconversion have been systematically investigated. 3.0 mM NH4+, 0.6% oat xylan in the media could enhance the yield of 10-DT; the optimum biocatalytic temperature was 26 degrees C and optimum pH value was 6.0. The highest conversion rate and yield of 10-DT from 7-XDT reached 92% and 764 mg/L, respectively. In addition, the biocatalytic capacity of the cell cultures remained 66.1% after continuous three batches. These results indicate that converting 7-XDT to 10-DT, a useful intermediate for the semisynthesis of paclitaxel or other taxane-based anticancer drugs by a novel bacterial strain, Enterobacter sp. CGMCC 2487, would be an alternative for the practical application in the future. (C) 2010 Elsevier B.V. All rights reserved.