Abstract

India generates 126.6 and 42 million tons of Rice straw (RS) and Rice husk (RH) annually, respectively. These agro-processing wastes feedstock are dumped in landfills or burnt, releasing toxic gases and particulate matter into the environment. This paper explores the valorization of these wastes feedstock into sustainable, economic products. We compare these wastes as matrices for lipase immobilization. These matrices were characterized, different parameters (pH, temperature, ionic strength, and metal ion cofactors) were checked, and the selected matrix was analyzed for reusability and hydrolysis of vegetable oils. Lipase immobilized Rice straw (LIRS) showed the highest activity with 72.84% protein loading. Field emission scanning electron microscopy (FESEM) demonstrated morphological changes after enzyme immobilization. FTIR showed no new bond formation, and immobilization data was fitted to Freundlich adsorption isotherm (with K = 12.18 mg/g, n_F = 4.5). The highest activity with protein loading, 91.05%, was observed at pH 8, 37 °C temperature, 50 mM ionic strength, and lipase activity doubled in the presence of Mg²⁺ ions. The LIRS retained 75% of its initial activity up to five cycles and efficiently hydrolyzed different oils. The results reflected that the LIRS system performs better and can be used to degrade oily waste.

摘要

印度每年分别生产 126.6 吨稻草 (RS) 和 4200 万吨稻壳 (RH)。这些农产品加工废物原料被倾倒在垃圾填埋场或焚烧，向环境中释放有毒气体和颗粒物。本文探讨了如何将这些废物原料转化为可持续的经济产品。我们将这些废物作为脂肪酶固定化的基质进行比较。对这些基质进行了表征，检查了不同的参数（pH、温度、离子强度和金属离子辅助因子），并对所选基质的可重复使用性和植物油的水解进行了分析。脂肪酶固定化稻秆 (LIRS) 显示出最高的活性，蛋白质负载量为 72.84%。场发射扫描电子显微镜（FESEM）显示酶固定化后的形态变化。FTIR 显示没有新的键形成，固定化数据符合 Freundlich 吸附等温线（K  = 12.18 mg/g，n _F  = 4.5）。^{在 pH 8、37 °C 温度、50 mM 离子强度下观察到蛋白质负载量最高，为 91.05%，并且在 Mg 2+}离子存在下脂肪酶活性加倍。LIRS 在五个循环中保留了 75% 的初始活性，并有效水解不同的油。结果表明，LIRS 系统性能更好，可用于降解含油废物。