Immobilized Inulinase on Grafted Alginate Beads Prepared by the One-Step and the Two-Steps Methods

Abstract

Grafted alginate beads were prepared using the Encapsulator by two methods, the one-step and the two-step. The methods of grafting were characterized by thermal gravimetric analysis and infrared (IR). The glass transition (Tg) of both grafted gel beads showed gradual thermal improvement over the control gel. However, the one-step method showed higher Tg (231 °C) compared to the two-step method (220 °C). Both methods were also evaluated for immobilization of an important industrial enzyme, inulinase, to produce fructose, which is good for diet regimens and suitable for diabetics. The one-step method showed an enzyme loading capacity (ELC) of 530 U/g gel beads compared to 336 U/g gel beads for the two-step method. Accordingly, the one-step method has been chosen for further optimization. The ELC has been optimized to reach 1627 U/g gel using our locally prepared crude enzyme compared to 10.9 U/g by another author using purified inulinase. The immobilization process improved as did the enzyme’s thermal stability, from 50 to 60 °C, which is the most suitable temperature used in food industries to prevent microbial contamination. The enzyme’s thermal stability test at 60 °C and for an incubation time of 2 h, revealed a drastic decrease of the free enzyme activity to 21%, compared to 89% retention of activity for the immobilized enzyme. The immobilization process improved as well the enzyme’s shelf stability, where the free enzyme lost all of its activity at room temperature after 28 days, the immobilized enzyme retained over 77% of its initial activity. These results are encouraging to produce high fructose syrup on the industrial scale as the carrier is efficient and the method is simple and economic.

Preparation of Zinc Tungstate (ZnWO4) Particles by Solvo-hydrothermal Technique and their Application as Support for Inulinase Immobilization

“…Figure 6 also demonstrates that the increase of the temperature had a negative effect in the improvement of enzyme adsorption, with loading capacity of 605 U.g -1 support and 264 U.g -1 support at 30 and 50 o C, respectively. For comparison purposes, Missau et al 16 found similar results regarding the inulinase immobilization on alginate-chitosan beads, achieving 668 U.g -1 gel beads at 50 o C. Grafted alginate beads showed an inulinase loading capacity of 530 U.g -1 gel beads 19 . Chitin 21 and silica 41 were used as inulinase supports, reaching 291 U.g -1 chitin and 43 U.g -1 silica, respectively.…”

“…It may produce high fructose syrups by enzymatic hydrolysis, and are used for the production of fructooligosaccharides, which are functional food ingredients. Inulinase has been immobilized by adsorption on different supports such as grafted alginate beads 19 , aminated non-porous silica 20 and chitin 21 . However, the inulinase immobilization using the ZnWO 4 oxide as support has not been explored yet.…”

The Art of Immobilization Using Biopolymers, Biomaterials and Nanobiotechnology

“…Immobilization of enzymes is one of the main methods used to stabilize free enzymes (Elnashar, 2010a;Danial et al, 2010). The support material and the main methods of immobilization are key parameters in enzyme immobilization.…”

“…They were alternatively immobilized on solid supports (Fig. 1b) so that they can be easily separated from the products by simple filtration or using a fluidized magnetized bed reactor system (Danial et al, 2010, Elnashar, 2010aElnashar et al, 2008Elnashar et al, , 2009aElnashar et al, , 2009bYassin 2009a, 2009b;Mansour et al, 2007).…”

Production of Copper and Cobalt Aluminate Spinels and Their Application As Supports for Inulinase Immobilization

“…In the immobilization process enzymes are trapped in a solid matrix, therefore, is possible the reuse and it will not be subjected to denaturation 25 . Several materials with different characteristics such as natural clay 26 , grafted alginate beads 27 , aminated non-porous silica nanoparticles 28 , chitin 29 , alginate-chitosan beads 30 , poly(EGDMA) cryogels 31 and carbon nanotubes 32 have been used as supports for inulinase immobilization by adsorption process. The immobilization process presents some advantages compared with free enzyme, which are the easily removed of the products from immobilized enzymes and possibility the continuous mode of operation 33 .…”