Immobilization of Dextranase Using Anionic Natural Polymer Alginate as a Matrix for the Degradation of a Long-Chain Biopolymer (Dextran)

Abstract

Alginate is an inexpensive, nontoxic, valuable biopolymer utilized in the study for the immobilization of commercially applicable biocatalyst dextranase. Dextranase was immobilized by an entrapment method, and alginate hydrogel spheres were synthesized after optimizing several parameters. A sodium alginate concentration of 4.0% was noticed to be suitable along with a calcium chloride concentration of 0.2 molar after providing a curing time of 20 minutes. After comparing the characteristics of the entrapped enzyme with those of the soluble one, it was observed that the characteristics were more or less the same except for the change in reaction time which was noticed to be prolonged in the case of entrapped dextranase while the change in temperature and pH optima was not observed. The variation in Vmax and Km values of dextranase after entrapment was also noted. However, after extensive stability examination studies, it was found that dextranase became more stable after entrapment; as a result, it retained more than 50% of its original activity at elevated temperature even after exposure for about 2.0 hours. The reusability of dextranase was up to 7.0 cycles after performing catalytic activity under constant condition.

Application of Immobilized Enzymes in Juice Clarification

“…Generally speaking, the immobilizing supports used for juice clarification need to meet the following four requirements: good thermal stability and physicochemical stability, low price and high safety for use in juice, good biocompatibility (which is conducive to the catalytic reaction of the), and high loading capacity (which does not lead to enzyme denaturation and inactivation). Magnetic nanoparticles [83], alginate [84], and chitosan [85] are commonly used as supports for immobilized enzymes in juice clarification. In recent years, researchers have also begun to study some new immobilization supports, including gelatin hydrogel [66], montmorillonite [78], and salinized glass beads [76].…”

“…Magnetic nanoparticles can be easily separated from a reaction medium under the condition of an external magnetic field, and their specific surface area is large, so they can load a large number of enzymes. Magnetic nanoparticles possess some advantages, such as their simple preparation, cost-effective synthesis, unique size, large specific surface area, high loading capacity for enzymes, low toxicity, chemically modifiable surface, biodegradability, biocompatibility [86], and ready dispersion in the aqueous phase [84]. Therefore, they are widely used in the immobilization of enzymes and have become potential supports.…”

“…Alginate also known as alginate gel is a kind of polysaccharide extracted from seaweed plants; it is non-toxic, has mild gelling properties [50,84], and is a natural polymer material [91]. At present, sodium alginate and calcium alginate are commonly used in research [15,24,62,68].…”

Polymers as Encapsulating Agents and Delivery Vehicles of Enzymes

“…They can easily undergo gelation with divalent cations under mild conditions suitable for the incorporation of biomacromolecules. Alginate-based microencapsulation is currently a favored approach for enzyme encapsulation [ 47 , 48 ]. A relatively simple and safe technique to entrap enzymes is the use of calcium alginate beads [ 49 , 50 , 51 ].…”