Encapsulation of lipase within metal-Organic framework (MOF) with enhanced activity intensified under ultrasound

In this study, lipase activity was augmented upto 1.6-folds after ultrasonic treatment at 22kHz and 11.38Wcm−2 for 25min. This highly activated lipase was encapsulated within zeolite imidazolate framework-8 (ZIF-8) as a metal-organic framework (MOF) material via facile one-step biomineralization method by simply mixing aqueous solution of 2-methylimidazole (13.3mmol), zinc acetate (1.33mmol) along with sonicated lipase within 10min at room temperature (28±2°C). The prepared lipase-MOF was characterized by using FT-IR, FT-Raman, XRD, BET, confocal scanning laser microscopy, TGA and SEM. Further, the thermal stability of lipase embedded MOF (in the range of 55–75°C) was evaluated in terms of half-life which showed 3.2 folds increment as against free lipase. In Michaelis–Menten kinetics studies, sonicated lipase entrapped MOF showed nearly same Km and Vmax values as that of sonicated free lipase. Moreover, the immobilized lipase exhibited up to 54% of residual activity after seven successive cycles of reuse, whereas it retained 90% of residual activity till twenty-five days of storage. Finally, the conformational changes occurred in lipase after sonication treatment and encapsulation within MOF were analyzed by using FT-IR data analysis tools and fluorescent spectroscopy. Graphical abstract
Source: Enzyme and Microbial Technology - Category: Biotechnology Source Type: research