Raghu Sujatha, Pennathur Gautam
Centre for Biotechnology, Anna University , Chennai , India.
Turk J Biol. 2018 Aug 9;42(4):307-318. doi: 10.3906/biy-1805-28. eCollection 2018.
A carboxylesterase isolated from Aeromonas caviae MTCC 7725 was immobilized by entrapping it in chitosan coated calcium alginate beads. This was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). The activity of the native and immobilized enzyme was measured at various temperatures, pH levels, and organic solvents. The optimum temperature for activity of the native enzyme was found to be 40 °C and this increased to 50 °C on immobilization. The immobilized enzyme showed enhanced stability and high residual activity in various organic solvents as compared to the free enzyme. An environmentally benign approach was used for the synthesis of ethyl salicylate using the immobilized enzyme. The product obtained was confirmed by GC-MS. The kinetic parameters, such as K m and Vmax, were also determined for the native and immobilized enzyme. The immobilized enzyme retained 50% of its activity after vfie cycles. The immobilized enzyme retained 80% and 40% of its activity at 4 °C and at 37 °C, respectively, at the end of 40 days. The results obtained from our study show that the immobilized enzyme can serve as a robust catalyst for industrial applications.
从豚鼠气单胞菌MTCC 7725中分离出的一种羧酸酯酶被包埋在壳聚糖包被的海藻酸钙珠中进行固定化。通过扫描电子显微镜（SEM）、能量色散X射线光谱（EDX）和傅里叶变换红外光谱（FTIR）对其进行了表征。在不同温度、pH值和有机溶剂条件下测定了天然酶和固定化酶的活性。发现天然酶活性的最适温度为40℃，固定化后提高到50℃。与游离酶相比，固定化酶在各种有机溶剂中表现出更高的稳定性和高残留活性。采用环境友好的方法，利用固定化酶合成水杨酸乙酯。通过气相色谱-质谱联用（GC-MS）对所得产物进行了确认。还测定了天然酶和固定化酶的动力学参数，如K m和Vmax。固定化酶在经过五个循环后仍保留其50%的活性。在40天结束时，固定化酶在4℃和37℃下分别保留其80%和40%的活性。我们的研究结果表明，固定化酶可作为工业应用中的一种强大催化剂。
