Gomes Fabrício M, Pereira Ernandes B, de Castro Heizir F
Biocatalysis Laboratory, Department of Chemical Engineering, Faculdade de Engenharia Química de Lorena, 12606-970 Lorena, SP, Brazil.
Biomacromolecules. 2004 Jan-Feb;5(1):17-23. doi: 10.1021/bm0342077.
Chitin was functionalized with hexamethylenediamine followed by glutaraldehyde activation, and its capacity to bind Candida rugosa lipase was investigated. The loading of 250 units g(-1) support showed to be effective, resulting in a uniform enzyme fixation with high catalytic activity. Both free and immobilized lipases were characterized by determining the activity profile as a function of pH, temperature, and thermal stability. For the immobilized lipase, the influence of the reaction temperature and substrate polarity in nonconventional biocatalysis was also analyzed. Production of butyl esters was found to be dependent on the substrate partition coefficient, which accounts the greatest value for the system butanol and butyric acid. The highest enzyme activity was found for the system butanol and caprylic acid at a reaction temperature of 40 degrees C. Under such conditions, the operational stability tests indicated that a small enzyme deactivation occurs after 12 batches, revealing a biocatalyst half-life of 426.7 h.
几丁质先用六亚甲基二胺进行功能化处理，随后通过戊二醛活化，接着研究了其结合皱褶假丝酵母脂肪酶的能力。每克载体负载250单位被证明是有效的，可实现酶的均匀固定且具有高催化活性。通过测定游离脂肪酶和固定化脂肪酶的活性曲线（作为pH、温度和热稳定性的函数）对它们进行了表征。对于固定化脂肪酶，还分析了反应温度和底物极性在非传统生物催化中的影响。发现丁酸酯的产生取决于底物分配系数，该系数在丁醇和丁酸体系中具有最大值。在40℃的反应温度下，丁醇和辛酸体系的酶活性最高。在这种条件下，操作稳定性测试表明，经过12批次后会发生少量酶失活，生物催化剂的半衰期为426.7小时。
