School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia.
School of Chemical and Energy Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia; Institute of Bioproduct Development, Universiti Teknologi Malaysia, Skudai, Johor 81310, Malaysia.
Int J Biol Macromol. 2020 Apr 1;148:1222-1231. doi: 10.1016/j.ijbiomac.2019.10.101. Epub 2019 Nov 20.
Enzymatic synthesis of maltooligosaccharides is hampered due to lack of stability of soluble enzyme. This limitation can be tackled by cross linked enzyme aggregates (CLEAs) immobilization approach. However, substrate diffusion is a major bottleneck in cross linking technology. Herein, CLEAs of maltogenic amylase from Bacillus lehensis G1 (Mag1) was developed with addition of porous agent (Mag1-p-CLEAs). Comparison of thermal, pH and kinetic analysis with CLEAs without porous agent (Mag1-CLEAs) and free Mag1 was performed. Mag1-p-CLEAs with porous structure prepared at 0.8% (w/v) of citrus pectin (porous agent), 0.25% (w/v) of chitosan (cross linker) and cross linked for 1.5 h yielded 91.20% activity. 80% of activity is retained after 30 min of incubation at 40 °C and showed longer half-life than free Mag1 and Mag1-CLEAs. Mag1-p-CLEAs also showed pH stability at acidic and alkaline pH. The 1.68-fold increase in V value in comparison to Mag1-CLEAs showed that the presence of pores of Mag1-p-CLEAs enhanced the beta-cyclodextrin accessibility. The increase in high catalytic efficiency (K/K) value, 1.90-fold and 1.05-fold showed that it also has better catalytic efficiency than free Mag1 and Mag1-CLEAs, respectively. Mag1-p-CLEAs not only improved substrate diffusibility of CLEAs, but also leads to higher thermal and pH stability of Mag1.
由于可溶性酶缺乏稳定性，导致麦芽寡糖的酶法合成受到阻碍。这种局限性可以通过交联酶聚集体（CLEAs）固定化方法来解决。然而，在交联技术中，底物扩散是一个主要的瓶颈。本文通过添加多孔剂（Mag1-p-CLEAs）的方法制备了地衣芽孢杆菌来源的麦芽糖淀粉酶（Mag1）的交联酶聚集体（CLEAs）。并对未添加多孔剂的 Mag1-CLEAs 和游离 Mag1 进行了热稳定性、pH 值和动力学分析比较。在 0.8%（w/v）柑橘果胶（多孔剂）、0.25%（w/v）壳聚糖（交联剂）和交联 1.5 h 的条件下制备的具有多孔结构的 Mag1-p-CLEAs 产率为 91.20%。在 40°C 孵育 30 min 后保留 80%的活性，半衰期长于游离 Mag1 和 Mag1-CLEAs。Mag1-p-CLEAs 在酸性和碱性 pH 值下也具有 pH 稳定性。与 Mag1-CLEAs 相比，V 值增加了 1.68 倍，表明 Mag1-p-CLEAs 中的孔的存在增强了β-环糊精的可及性。高催化效率（K/K）值增加了 1.90 倍和 1.05 倍，表明它比游离 Mag1 和 Mag1-CLEAs 具有更好的催化效率。Mag1-p-CLEAs 不仅提高了 CLEAs 的底物扩散性，而且还提高了 Mag1 的热稳定性和 pH 值稳定性。
