Chitin/graphene oxide (Ch/GO) composite aerogel beads were fabricated by a simple and environmentally friendly method for lipase immobilization. The morphology and specific surface area of these beads were investigated by scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET), respectively. The results revealed that the prepared beads showed three-dimensional porous structure, and GO was successfully bound to chitin with enhanced surface area and mechanical strength. Candida rugose lipase (CRL) was immobilized on Ch/GO aerogel beads under optimum conditions by adsorption and subsequent cross-linking with glutaraldehyde which is added in the presence of the unbound proteins by conjugation. The maximum immobilization capacity of Ch, Ch/GO-5, Ch/GO-10 were 129.9, 141.1, 151.9 mg/g_support. The immobilized lipases exhibited good temperature and thermal stability in comparison to free CRL. After recycling 5 times, the immobilized lipases remained more than 90% of their initial activity and the activity of Ch/GO-10 could remain 84.2% of free CRL. With these desired characteristics, the design of Ch/GO composite aerogel beads for lipase immobilization may have potential applications in various lipase-based industrial processes.

中文翻译：

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固定化脂肪酶的几丁质/氧化石墨烯复合气凝胶微珠的合成

甲壳素/氧化石墨烯（Ch / GO）复合气凝胶珠是通过简单且环保的脂肪酶固定方法制备的。这些珠子的形态和比表面积分别通过扫描电子显微镜（SEM）和Brunauer–Emmett–Teller（BET）进行了研究。结果表明，制得的珠粒具有三维多孔结构，GO与几丁质成功结合，表面积和机械强度提高。在最佳条件下，通过吸附并随后与戊二醛交联将假丝酵母（Candida rugose）脂肪酶（CRL）固定在Ch / GO气凝胶珠上，戊二醛在未结合的蛋白质存在下通过缀合添加。Ch，Ch / GO-5，Ch / GO-10的最大固定容量为129.9、141.1、151.9 mg / g_支持。与游离的CRL相比，固定化的脂肪酶表现出良好的温度和热稳定性。回收5次后，固定化的脂肪酶仍保持其初始活性的90％以上，而Ch / GO-10的活性可以保持游离CRL的84.2％。具有这些期望的特性，用于脂肪酶固定化的Ch / GO复合气凝胶珠的设计可能在各种基于脂肪酶的工业过程中具有潜在的应用。