Santos Julio C, Mijone Patrícia D, Nunes Gisele F M, Perez Victor H, de Castro Heizir F
Engineering School of Lorena-University of São Paulo, PO Box 116, Lorena 12-602.810, SP, Brazil.
Colloids Surf B Biointerfaces. 2008 Feb 15;61(2):229-36. doi: 10.1016/j.colsurfb.2007.08.006. Epub 2007 Aug 21.
Candida rugosa lipase was immobilized by covalent binding on hybrid matrix of polysiloxane-polyvinyl alcohol chemically modified with different activating agents as glutaraldehyde, sodium metaperiodate and carbonyldiimidazole. The experimental results suggested that functional activating agents render different interactions between enzyme and support, producing consequently alterations in the optimal reaction conditions. Properties of the immobilized systems were assessed and their performance on hydrolytic and synthetic reactions were evaluated and compared with the free enzyme. In hydrolytic reactions using p-nitrophenyl palmitate as substrate all immobilized systems showed higher thermal stability and optima pH and temperature values in relation to the free lipase. Among the activating compounds, carbonyldiimidazole resulted in a total recovery of activity on the support and the highest thermal stability. For the butyl butyrate synthesis, the best performance (molar conversion of 95% and volumetric productivity of 2.33 g L(-1)h(-1)) was attained with the lipase immobilized on POS-PVA activated with sodium metaperiodate. The properties of the support and immobilized derivatives were also evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopies and chemical composition (FTIR).
通过共价结合将皱褶假丝酵母脂肪酶固定在经不同活化剂(如戊二醛、高碘酸钠和羰基二咪唑)化学修饰的聚硅氧烷 - 聚乙烯醇杂化基质上。实验结果表明,功能性活化剂使酶与载体之间产生不同的相互作用,从而导致最佳反应条件发生改变。对固定化体系的性质进行了评估,并评价了它们在水解反应和合成反应中的性能,并与游离酶进行了比较。在以对硝基苯基棕榈酸酯为底物的水解反应中,所有固定化体系相对于游离脂肪酶均表现出更高的热稳定性以及最佳pH值和温度值。在这些活化化合物中,羰基二咪唑使载体上的活性完全恢复,并且热稳定性最高。对于丁酸丁酯的合成,用高碘酸钠活化的POS - PVA固定化脂肪酶表现出最佳性能(摩尔转化率为95%,体积产率为2.33 g L⁻¹h⁻¹)。还通过扫描电子显微镜(SEM)、能量色散X射线光谱和化学成分(FTIR)对载体和固定化衍生物的性质进行了评估。