α-淀粉酶和糖化酶协同酶解葛根淀粉动力学研究

Hydrolysis Kinetics of Kudzu Starch with α-Amylase and Glucoamylase

研究α-淀粉酶和糖化酶协同作用水解葛根淀粉分子,并建立酶解动力学模型。研究α-淀粉酶和糖化酶在单酶体系、双酶体系、不同淀粉颗粒粒径、不同酶用量的组合对还原性糖形成的影响,以此确定淀粉水解模式和最佳酶用量的组合。基于淀粉颗粒粒径能影响淀粉水解,修正现有的α-淀粉酶和糖化酶协同酶解淀粉动力学方程,并研究葛根淀粉初始质量浓度和不同酶用量组合对解淀粉动力学模型有效性影响。结果表明:单酶体系与双酶体系对还原糖的形成速率差异显著(P<0.01);α-淀粉酶和糖化酶具有协同作用,α-淀粉酶用量为20U和糖化酶为36U为最佳酶组合;对修正的酶解动力学模型进行验证,结果表明修正的酶解动力学模型只有在葛根淀粉初始质量浓度≤18.5mg/mL、α-淀粉酶和糖化酶在较低酶浓度的组合条件下才有效。

The synergistic hydrolysis efficiency of Kudzu starch with α-amylase and glucoamylase was evaluated and a model of enzymatic hydrolysis kinetics was established in our study.The effects of single α-amylase system followed by single glucoamylase system,mixed α-amylase and glucoamylase system,starch granules with different sizes and α-amylase/glucoamylase combination with different ratios on reducing sugar formation were investigated to determine the pattern of starch hydrolysis and the optimal α-amylase/glucoamylase combination.Based on starch granules with different sizes and experimental data as well as previous studies,a modified kinetic model for the hydrolysis of Kudzu starch with the combination of α-amylase and glucoamylase was established.At the same time,the effects of initial concentration of Kudzu starch and different α-amylase/glucoamylase combinations on the model of enzyme kinetics were also investigated in this paper.The kinetic constants were determined and the model was verified through multiple experiments.These results showed a significant difference（P0.01） in the rate of reducing sugar formation between single enzyme system and mixed enzyme system.The α-amylase exhibited a high synergistic effect on glucoamylase.The optimal α-amylase/glucoamylase combinations were α-amylase concentration of 20 U and glucoamylase concentration of 36 U.Finally,these results also showed that the model of enzymatic hydrolysis kinetics was valid only if the initial concentration of Kudzu starch was not more than 18.5 mg/mL,and the concentrations of α-amylase and glucoamylase were less than 40 U and 72 U,respectively.