Laccase Immobilized Fe3O4-Graphene Oxide Nanobiocatalyst Improves Stability and Immobilization Efficiency in the Green Preparation of Sulfa Drugs

Abstract

This paper, reports on the novel and green synthesis procedure for sulfonamides that involved the immobilization of Trametes Versicolor laccase onto the Fe3O4–graphene nanocomposite via glutaraldehyde (GA) crosslinking (Lac/Fe3O4/GO). Various parameters, mainly, activation time, GA, and laccase concentration were investigated and optimized. The results showed that the optimal contact time was 4 h, GA concentration was 5% while laccase concentration was 5 mg·mL−1, at which a high enzyme activity recovery was achieved (86%). In terms of the stability of immobilized laccase to temperature and storage conditions, the performance of the nanobiocatalyst was found to significantly exceed that of free laccase. The results have indicated that nearly 70% of relative activity for immobilized laccase remained after the incubation period of 2 h at 55 °C, but only 48% of free laccase remained within the same time period. Moreover, the immobilized laccase retained 88% of its initial activity after storage for 20 days. In case of the free laccase, the activity retained within the same time period was 32%. In addition, the nanobiocatalyst possessed better recycling performance as evidenced from the observation that after eight cycles of repeated use, it retained 85% of its original activity.

Preparation and characterization of oxidized Multi-walled Carbon Nanotubes-Immobilized Aspergillus sp. Laccase Hybrid Materials

“…This was done by incubating the immobilized and free enzyme in a buffer (pH 3) at different temperatures (50 and 70ºC) for 1 h. After that the activities were determined as shown in Fig 6b . It was observed that when the temperature was increased up to 70 ºC, the free enzyme loses up to 80% of its activity, whereas the immobilized enzyme retains 45% of its relative activity under the same conditions. The inhibition in the free enzyme activity at a high temperature has also been previously reported [56]. Based on these results, laccase immobilization onto ox-MWCNTs improved the thermal stability of the immobilized enzyme relative to the free one.…”

Improvement of Laccase Activity Via Covalent Immobilization over Mesoporous Silica Coated Magnetic Multiwalled Carbon Nanotubes for the Discoloration of Synthetic Dyes

“…This cross-linker has two aldehyde functional groups; one is capable of covalently reacting with the support, while the other reacts with the amino groups of enzymes, leading to the immobilization of enzymes. 22,39,40 To further investigate the influence of glutaraldehyde concentrations on the immobilization of laccase, diverse glutaraldehyde concentrations were tested. As indicated in Figure S3a, the activity of the biocatalytic system (laccase@ Fe 3 O 4 -MWCNT@SiO 2 ) was augmented with the rising initial glutaraldehyde concentrations from 1 to 1.5 wt %, and the optimum relative activity was obtained with the use of a 1.5 wt % glutaraldehyde concentration.…”

Surface-coated magnetic nanostructured materials for robust bio-catalysis and biomedical applications-A review

“…GO-MNPs immobilized lipase showed activity at elevated temperatures retaining over 90% of its recovered activity at 60 °C, whereas the soluble enzyme could preserve only 45% of its activity [82] . Rouhani et al (2020) immobilized laccase from T. versicolor onto magnetic-graphene nanocomposites via glutaraldehyde crosslinking for the green preparation of sulfa drugs [83] . For this, magnetic GO nanocomposite was first fabricated by in situ co-precipitation method and then functionalized with APTES followed by cross-linking with glutaraldehyde.…”

“… Nanobioconjugate preserved higher than 85% of its activity after 20 days of storage and possessed satisfactory recycling efficiency exhibiting 85% of its original activity after eight repeated cycles. Green preparation of sulfa drugs [83] Biomimetic silica-MNPs hybrid nanocomposite β -glucuronidase from Patella vulgata limpets silica Superior storage, thermal, and operational stability of the enzyme immobilized in the composite material. Different bioconjugates with MNPs and Si maintained 40% of their original activities at a high temperature of 80 °C after 6 h, while the free form of enzyme dropped over 90% of its activity within 10 min.…”