Optimum Lipase Immobilized on Diamine-Grafted PVDF Membrane and Its Characterization

Abstract

A facile and economic modification of polyvinylidene fluoride (PVDF) with an orientation of diamine is presented herein. The physical characterizations of native and diamine-grafted PVDF membranes are analyzed by three different techniques: the ninhydrin test, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The diamine-grafted PVDF is activated by glutaraldehyde for enzyme immobilization. The response surface methodology (RSM) is used to search the optimal immobilization conditions and to understand the significance of the factors affecting the responses of immobilized lipase. The optimal conditions for lipase immobilization are: a reaction time of 90 min, temperature of 35 degrees C, pH of 6, and an enzyme concentration of 7 mg/mL. An experiment performed under the optimum conditions obtains lipase activity of 60 U per g of membrane. A good agreement between the calculated and experimental values is thereby achieved

Immobilization of lipase on biocompatible co-polymer of polyvinyl alcohol and chitosan for synthesis of laurate compounds in supercritical carbon dioxide using response surface methodology

“…It is essential to know the possible support-lipase interaction and immobilization mechanism to achieve higher activity-stability of immobilized lipase and to avoid random denaturation of enzyme after immobilization [26][27][28][29][30][31][32][33]. In the present study, an entrapment methodology was used for immobilization of lipase BCL since, immobilization of lipase within polymer matrix was carried out at the time of PVA:CHI matrix formation [26,27].…”

“…Also, it is expected that, lipases not only entrapped within the PVA:CHI polymer matrix, but also forms an extra multi-point interaction within the matrix via H-bonding, covalent, and hydrophobic interactions, which produces an efficient stable and robust biocatalyst [28,29]. Basically free OH of PVA and CHI leads to form H-bonding, [30,31]. Thus hydrophobic support enhances the phenomenon of lipase immobilization [26,27,29,31].…”

“…Basically free OH of PVA and CHI leads to form H-bonding, [30,31]. Thus hydrophobic support enhances the phenomenon of lipase immobilization [26,27,29,31]. In addition to this, entrapment methodology has several advantages such as (i) it is simple, (ii) it is usually free from the use of cross-linking chemical agent, (iii) it does not involve multistep immobilization process and (iv) moreover, entrapment methodology shields enzyme molecules by direct exposure of outer reaction environment, which ultimately enhances the stability and activity of biocatalyst in reaction media.…”

“…This hyperactivation was attributed to dynamic interfacial activation of lipase on hydrophobic support [31,32]. The hydrophobic support-lipase interactions promote stabilization of active (open) state conformation of lipase molecules [32].…”

Kinetics and optimization of lipase-catalyzed synthesis of rose fragrance 2-phenylethyl acetate through transesterification

“…Briefly, the PVDF membrane (∼150 mg, d: 47 mm, pore size: 0.45 m, thickness: 140 m) was aminated with 1,4-diaminobutane, and then activated with glutaraldehyde. The amine content of the PVDF-DA membrane was determined to be 0.252 mmol g −1 membrane by using ninhydrin method [24]. The lipase immobilization was performed through immersion of the pre-activated PVDF membrane in 20 mL of 50 mM, pH 6 phosphate buffer with a lipase concentration of 7 mg mL −1 (140 mg) at 35 • C for 90 min.…”