Department of Chemical Engineering, National Institute of Technology Andhra Pradesh, Tadepalliguem, Andhra Pradesh, India; Biochemical Engineering Research Group, Department of Biotechnology, National Institute of Technology Andhra Pradesh, Tadepalligudem, Andhra Pradesh, India.
School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India.
Int J Biol Macromol. 2024 Oct;277(Pt 2):134133. doi: 10.1016/j.ijbiomac.2024.134133. Epub 2024 Jul 27.
In recent years, numerous attempts have been made to develop a low-cost adsorbent for selectively recovering industrially important products from fermentation broth or complex mixtures. The current study is a novel attempt to selectively adsorb esterase from Trichoderma harzianum using cheap adsorbents like bentonite (BT), activated charcoal (AC), silicon dioxide (SiO), and titanium dioxide (TiO). AC had the highest esterase adsorption of 97.58% due to its larger surface area of 594.45 m/g. SiO was found to have the highest selectivity over esterase, with an estimated purification fold of 7.2. Interestingly, the purification fold of 5.5 was found in the BT-extracted fermentation broth. The functional (FT-IR) and morphological analysis (SEM-EDX) were used to characterize the adsorption of esterase. Esterase adsorption on AC, SiO, and TiO was well fitted by Freundlich isotherm, demonstrating multilayer adsorption of esterase. A pseudo-second-order kinetic model was developed for esterase adsorption in various adsorbents. Thermodynamic analysis revealed that adsorption is an endothermic process. AC has the lowest Gibbs free energy of -10.96 kJ/mol, which supports the spontaneous maximum adsorption of both esterase and protein. In the desorption study, the maximum recovery of esterase from TiO using sodium chloride was 41.34 %. Unlike other adsorbents, the AC-adsorbed esterase maintained its catalytic activity and stability, implying that it could be used as an immobilization system for commercial applications. According to the kinetic analysis, the overall rate of the reaction was controlled by reaction kinetics rather than external mass transfer resistance, as indicated by the Damkohler number.
近年来，人们尝试开发低成本的吸附剂，以从发酵液或复杂混合物中选择性地回收工业上重要的产品。本研究试图使用廉价的吸附剂如膨润土（BT）、活性炭（AC）、二氧化硅（SiO）和二氧化钛（TiO）来选择性地从哈茨木霉中吸附酯酶。由于其更大的表面积为 594.45 m/g，AC 具有最高的酯酶吸附率 97.58%。SiO 对酯酶具有最高的选择性，估计其纯化倍数为 7.2。有趣的是，在 BT 提取的发酵液中发现了 5.5 的纯化倍数。功能（FT-IR）和形态分析（SEM-EDX）用于表征酯酶的吸附。AC、SiO 和 TiO 上的酯酶吸附均很好地符合 Freundlich 等温线，表明酯酶的多层吸附。为各种吸附剂中的酯酶吸附开发了拟二级动力学模型。热力学分析表明吸附是一个吸热过程。AC 的吉布斯自由能最低为-10.96 kJ/mol，这支持酯酶和蛋白质的最大自发吸附。在解吸研究中，使用氯化钠从 TiO 中最大回收 41.34%的酯酶。与其他吸附剂不同，AC 吸附的酯酶保持其催化活性和稳定性，这意味着它可用于商业应用的固定化系统。根据动力学分析，反应的总速率受反应动力学控制，而不是外部质量传递阻力，如 Damkohler 数所示。
