School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile.
Appl Biochem Biotechnol. 2011 Nov;165(5-6):1332-41. doi: 10.1007/s12010-011-9350-8. Epub 2011 Sep 2.
Lipase from Pseudomonas stutzeri PL-836 was immobilized on hydrophobic supports and evaluated in the transesterification of wood sterols in solvent-free and solvent-containing media. Triton X-100 was used as additive during immobilization in butyl and octadecyl sepabeads increasing enzyme activity yield by 5% and 60%, respectively. Hyperactivation was observed during immobilization in EC octadecyl sepabeads with enzyme activity yield of 200% and protein immobilization yield of 93%. Thermostability of the immobilized enzyme was assessed at 50 °C in different media in the absence and presence of exogenous solvents. The presence of Triton X-100 during immobilization reduced enzyme stability while tert-butanol increased it. Transesterification in solvent-free and solvent-containing medium with lipase immobilized in EC octadecyl sepabeads showed that the presence of exogenous solvent increased both conversion yield and productivity. At rather high levels of biocatalyst hydration (40% on wet basis) the presence of tert-butanol in the reaction medium more than doubled conversion yield and productivity.
从恶臭假单胞菌 PL-836 中提取的脂肪酶被固定在疏水性载体上，并在无溶剂和含溶剂的介质中评估其对木甾醇的酯交换反应。在丁基和十八烷基 sepabeads 中进行固定化时，使用 Triton X-100 作为添加剂，分别使酶活产率提高了 5%和 60%。在 EC 十八烷基 sepabeads 中进行固定化时观察到超活化，酶活产率为 200%，蛋白固定化产率为 93%。在无和有外源溶剂的情况下，在不同介质中于 50°C 下评估固定化酶的热稳定性。在固定化过程中加入 Triton X-100 会降低酶的稳定性，而叔丁醇则会提高酶的稳定性。用固定在 EC 十八烷基 sepabeads 上的脂肪酶在无溶剂和含溶剂的介质中进行酯交换反应表明，外源溶剂的存在提高了转化率和生产效率。在相当高的生物催化剂水合水平（湿基 40%）下，反应介质中叔丁醇的存在使转化率和生产效率提高了一倍以上。
