Inulinase immobilization on polyethylene glycol/polypyrrole multiwall carbon nanotubes producing a catalyst with enhanced thermal and operational stability

Abstract

This paper describes the development of a simple method for mixed non‐covalent and covalent bonding of partially purified inulinase on functionalized multiwall carbon nanotubes (f‐MWCNTs) with polypyrrole (PPy). The pyrrole (Py) was electrochemically polymerized on MWCNTs in order to fabricate MWCNTs/PPy nanocomposite. Two multiple forms of enzyme were bound to N‐H functional groups from PPy and ‐COO− from activated MWCNTs to yield a stable MWCNTs/PPy/PEG immobilized preparation with increased thermal stability. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to confirm functionalization of nanoparticles and immobilization of the enzyme. The immobilization yield of 85% and optimal enzyme load of 345 μg protein onto MWCNTs was obtained. The optimum reaction conditions and kinetic parameters were established using the UV‐Vis analytical assay. The best functional performance for prepared heterogeneous catalyst has been observed at pH 3.6 and 10, and at the temperatures of 60 and 80ºC. The half‐life (t1/2) of the immobilized inulinase at 60 and 80ºC was found to be 231 and 99 min, respectively. The reusability of the immobilized formulation was evaluated based on a method in which the enzyme retained 50% of its initial activity, which occurred after the eighteenth operation cycle.

Production of Cardamine violifolia selenium-enriched peptide using immobilized Alcalase on Fe3O4 modified by tannic acid and polyethyleneimine

“… 39 After the first four cycles, the activity of immobilized Alcalase reduced gently, probably because of the slow inactivation of Alcalase upon use. 40 Nevertheless, unlike the free Alcalase which could only be used once, the enzyme activity of immobilized Alcalase could still reach 61 ± 1.2% of the initial activity after 10 times reuse, which greatly reduced the costs.…”

Engineering Mussel-Inspired Coating on Membranes for Green Enzyme Immobilization and Hyperstable Reuse

“…From the second to the eighth reuse, its relative activity declined gently, which might be related to the slow deactivation of the enzyme. 27 Finally, after 8 reuse, the TA/APTES-E and TA/AEAPTES-E retained 81% and 78% of their initial activity, respectively. These results indicated the excellent reusability of our immobilized enzyme compared to other studies, which achieved an activity retention of 23% after 6 cycles, 28 70% after 5 cycles, 29 and 72% after 7 cycles.…”

“…After the first use, the activity of the immobilized enzyme decreased obviously as the detachment of weakly bonded enzyme. From the second to the eighth reuse, its relative activity declined gently, which might be related to the slow deactivation of the enzyme . Finally, after 8 reuse, the TA/APTES-E and TA/AEAPTES-E retained 81% and 78% of their initial activity, respectively.…”

Bioinspired Lipase Immobilized Membrane for Improving Hesperidin Lipophilization

“…In order to evaluate the reusability, nine cycles of repeated experiments were conducted. As shown in Figure 9 e, the relative activity of CAL-B@PES decreased by 78% after the ninth cycle, because some weak binding enzyme was lost during the long-term operation [ 47 ]. The residual activity of CAL-B@PDA/PES decreased by about 60%, because of the removal of immobilized free CAL-B from PDA/PES, mechanical damage in the reaction process, and the erosion of weak CAL-B during the washing process [ 10 ].…”