Abstract
Taxoid 10β-O-acetyltransferase (DBAT) is the key enzyme to produce baccatin III, a key precursor in paclitaxel synthesis, by acetyl group transfer from acetyl-CoA to the C10 hydroxyl of 10-deacetylbaccatin III. In this study, the recombinant DBAT (rDBAT) was immobilized by cross-linked enzyme aggregates (CLEAs). To further optimize the enzyme recovery, single-factor experiment and response surface methodology were applied. 60% ammonium sulfate as precipitant, 0.05% glutaraldehyde as fixing agent, pH 7.0, 2 h as cross-linking time, 30 °C as cross-linking temperature were confirmed to be the optimum conditions to prepare the CLEAs-rDBAT in single-factor experiment. In addition, 62% for ammonium sulfate saturation, 0.15% for glutaraldehyde, and pH 6.75 were confirmed to be the optimum conditions with averagely 73.9% activity recovery in 3 replications, which was consistent with the prediction of response surface methodology. After cross-linking, the optimum temperature of CLEAs-rDBAT rose up to 70 °C and CLEAs-rDBAT could be recycled for three times.
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