脂肪酶固定化及其在食品领域中应用的研究进展

为构建新型固定化酶催化体系，以聚甲基丙烯酸缩水甘油酯为载体，利用贻贝仿生技术——多巴胺/聚乙烯亚胺共沉积进行修饰，采用扫描电镜（SEM）、能谱（EDS）、Zeta电位及红外光谱（FT-IR）表征所得材料，并研究其固定化近平滑假丝酵母CICC 33470所产脂肪酶的表征及酶学性质。最佳酶固定化条件为：固定化温度为30 ℃，固定化pH为7.0，固定化时间为5 h，初始酶活为337.76 U/mL，载体添加量为0.2 g。固定化酶最佳反应温度为50 ℃，最佳反应pH为8.0，最佳反应时间为10 min，最优条件下固定化酶酶活为484.42±5.97 U/g-载体。固定化酶的稳定性明显提高，重复使用8次后，固定化酶仍有39.22%的初始酶活。进一步将固定化酶用于催化乙酰丙酸与十二醇的酯化反应，转化率可达75.94%，充分证明聚甲基丙烯酸缩水甘油酯经修饰后是固定化脂肪酶的优良载体，为未来扩大脂肪酶的应用范围提供了基础数据。

Opportunities for improving biodiesel production via lipase catalysis

In order to construct a new type of immobilized enzyme catalytic system, poly (glycidyl methacrylate) was used as a support, and was modified with dopamine/polyethyleneimine by the mussel-inspired co-deposition method. The resulted material was characterized by scanning electron microscope (SEM), energy spectroscopy (EDS), Zeta potential and Fourier transform infrared spectrometer (FT-IR), respectively. Then, the resulted material was applied for the immobilization of lipase, which was fermented via Candida parapsilosis CICC 33470. The characterization and enzymatic properties of immobilized enzyme were also investigated. The optimal immobilized conditions were the immobilization temperature of 30 ℃, the immobilization pH of 7.0, the immobilization time of 5 h and the immobilization initial enzyme acticity of 337.76 U/mL, together with the carrier addition of 0.2 g. It was indicated that the maximum enzyme activity reached 484.42±5.97 U/g-support, as the optimal reaction temperature, reaction pH and reaction time were 50 ℃, 8.0 and 10 min, respectively. In addition, the immobilized lipase exhibited excellent stability, and it kept 39.22% of original enzyme activity after eight reuse cycles. Furthermore, when the immobilized lipase was used to catalyze the esterification reaction of levulinic acid and lauryl alcohol, the conversion rate could reach 75.94%. It was illuminated that the modified poly (glycidyl methacrylate) could serve as a good support for lipase immobilization, and the results provided basic data for expanding the application areas of lipase in the future.