Thiol and urea functionalized magnetic nanoparticles with highly enhanced loading capacity and thermal stability for lipase in transesterification

Abstract

Magnetic nanoparticles (MNPs) were prepared by a co-precipitation method and thiol and urea functionalized using (3-mercaptopropyl) trimethoxysilane (MPTS) and 1-(3-trimethoxysilyl propyl) urea (TMSPU). The samples were characterized by SEM, XRD and FTIR, and BET surface area measurement and used for immobilization of Candida rugosa lipase type VII (CRL7) and Thermomyces lanuginosus lipase (TLL) for a transesterification reaction. The loading capacities of the lipases immobilized on the functionalized MNPs were also studied. The activity and thermal stability of the immobilized lipases were compared to those of the free enzymes too. The loading capacities of CRL7 and TLL on MNPs-TMSPU are 410 and 440 mg/g-MNPs , 5.9 and 5.5 times higher than those on the unfunctionalized MNPs, respectively. The initial activities of both CRL7 and TLL on MNPs-TMSPU are higher than those on MNPs-MPTS. After 30 min incubation at 80 o C, the remained activity of TLL on MNPs-TMSPU is 2.5 times higher than that of the free enzyme. The remained activities of the biocomposites assayed after each use in transesterification reaction demonstrate that TLL-MNPs-TMSPU biocomposite has a high yield of 92%. The immobilized TLL on MNPs-TMSPU and MPTS retain 80% and 70% of their initial activities after 8 times reuse, respectively. The functionalized MNPs are magnetically separated for reuse.

Improvement of adhesion properties of enzyme‐loaded coating on random packing in transesterification

“…The electrostatic attraction between oppositely charged active amino groups on the coating and carboxyl groups of the lipase can be the main cause of the lipases immobilization. Zeinab Salehi et al synthesized Fe 3 O 4 magnetic nanoparticles, functionalized with UPS containing amine groups and used for immobilization of Candida rugosa lipase Type VII and Thermomyces lanuginosus lipase for transesterification reactions . The functionalization dramatically enhances the lipases loading capacity and thermal stability.…”

“…FT‐IR can reflect the changes of functional groups on the surface of gel after the modifications, the peaks at 1,651 cm −1 become strong, indicating that the number of carboxyl group on the coating increases. The bands around 1,556 cm −1 and 3,400 cm −1 are attributed to the NH 2 bending of free NH 2 group from CALB and N–H stretching vibration, respectively . The addition of UPS has an effect on the N–H bond of the enzyme.…”

“…However, modification has a certain effect on enzyme activity. The chemical bond immobilization highly affects the enzyme conformation and possibly its secondary structure or limits the accessibility of substrate to the active site of the enzyme . Generally speaking, the catalytic efficiency of enzymes is much higher than that of inorganic catalysts.…”

Lipase immobilized on functionalized superparamagnetic few-layer graphene oxide as an efficient nanobiocatalyst for biodiesel production from Chlorella vulgaris bio-oil

“…Different nanostructure materials have been used as support for the immobilization of enzymes. A variety of nanostructures such as nanoparticles, polymer nanofibers and nanocomposites, metal organic frameworks, nano-and mesoporous silica, carbon nanotubes, graphene, and graphene oxide have been used for enzyme immobilization [20][21][22][23][24]. The magnetic nanoparticles have been known as very useful material in different applications.…”

Comparação Do Desempenho Catalítico a Partir Da Combinação De Lipases Livres E Imobilizadas Na Síntere De Ésteres Etílicos

“…Ainda pode-se notar a melhora no desempenho catalítico das enzimas após imobilizadas. Isso pode ter ocorrido devido ao processo de imobilização por ligação covalente, pois este pode restringir as mudanças conformacionais das enzimas, proporcionando maior estabilidade à temperatura e à presença de álcoois de cadeia curta em relação às enzimas livres (Salehi et al, 2016).…”