Bio-applications of chitosan

Abstract

Efficient commercial carriers suitable for the immobilization of enzymes are economically expensive. Contrarily, the immobilization techniques would enable the reusability of enzymes for tens of times, thus significantly reducing both enzyme and product costs. To prepare a novel carrier for enzyme immobilization it is, accordingly advantageous, that the utilizable starting materials are among those already, permitted for pharmaceutical or food industrial use. Carrageenans and chitosans are two commercially available polysaccharide families, belonging to this category having in addition, diverse features and reasonable costs. Unfortunately, chitosan is not individually manipulated, as it has low physical/mechanical stability, while carrageenan, in addition to its low thermal stability, is lacking the active functionalities required to covalently bind enzymes. In our laboratory, we have succeeded in assembling a combination of the two biopolymers, in such a way to gain the benefits of both, such as the abundance of active functional amino (NH2) groups of chitosans, and being shapeable, while having good thermal stability for carrageenan gel. Carrageenan gels were treated with protonated polyamines "chitosan" to form a polyelectrolyte complex, which was then followed by glutaraldehyde treatment. The newly developed carrier revealed an outstanding gel's thermal stability as it was augmented from 35 to 95°C. The novel gel incorporating the aldehydic chemical functionality has been efficaciously manipulated to covalently immobilize enzymes. FTIR techniques, as well as Schiff's base color development were used to elucidate the structure of the newly grafted carrier biopolymer. FTIR, equally confirmed the incorporation of the aldehydic carbonyl group to the carrageenan coated chitosan at via tracing the band 1720 cm-1. Interestingly, the operational stability retained 97% of the enzyme activity, even after 15 time uses. In brief, the newly developed immobilization methodology is simple and the carriers are economically favored vis à vis the commercially available Eupergit C® or Agaroses®, yet effective and utilizable for the immobilization of other enzymes. © 2012 by Nova Science Publishers, Inc. All rights reserved.