| In order to obtain a higher yield of α-cyclodextrin conversion, we use a single factor experiment and response surface experiment method, to optimize the production of α-cyclodextrin conditions by α-cyclodextrin glucosyltransferase. The enzyme is derived from strain Y112. First, the single factor method was used to screen six factors including substrate species, substrate concentration, enzyme content, reaction time, temperature, and pH. Second, these main variables affecting the conversion of α-cyclodextrin were evaluated with the Plackett-Burman test. The results suggested that substrate concentration, temperature, and pH were the most impactful factors. Finally, the optimal levels of the three factors were determined with central composite design and Design-Expert 8.05 software. The optimum conversion conditions were shown as follows: the concentration of potato starch was 5%, the amount of enzyme 200 U/g (starch), pH 8.4, 200 r/min, reacted at 30℃ for 6 h. Under the optimized conditions, the average value of α-CD conversion was 28.67%, which was an increase of 2.48 times compared with the pre-optimization yield. |
