Studies on the properties of Celluclast/Eudragit L-100 conjugate

Abstract

A cellulase from Trichoderma reesei was immobilized on Eudragit L-100, a reversibly soluble polymer depending on the pH of the medium. The solubility of the modified cellulase was studied at different pH values. By changing the pH, the adsorption equilibrium of the derivatized proteins is switched towards the liquid phase, thus making recycling possible. This method allows for improved stability, without major loss of specific activity. The adsorption of cellulase on Eudragit lowers the enthalpy of denaturation, but affects only slightly the denaturation temperature. The use of carbodiimide was ineffective on linking the enzymes covalently to the polymer, since the immobilization process was found to be only mediated by non-covalent forces. #

Hydrolysis of Lignocellulosic Biomass: Current Status of Processes and Technologies and Future Perspectives

“…This method allowed to improve the stability of the enzymes without significant loss of its specific activity. The adsorption of cellulases on Eudragit lowered the enthalpy of denaturation, but affected only slightly the denaturation temperature (Dourado et al, 2002).…”

“…Immobilization of cellulases via covalent bonds appears to be the most suitable technique. Besides the enzyme stabilization, the covalent-immobilization allows the use of supported enzymes for several cycles of reactions (Brady & Joordan, 2009;Li et al, 2007;Mateo et al, 2007;Dourado et al, 2002;Yuan et al, 1999). In 1999, Yuan and coworkers, immobilized cellulases onto acrylamide grafted acrylonitrile copolymer membranes (PAN) by means of glutaraldehyde.…”

Lignocellulose biotechnology: issues of bioconversion and enzyme production

“…Persson et al (1991) has covered issues of strain improvement, choice of substrate and culture conditions in relation to improvement of fungal cellulolytic enzyme production. Other investigators have looked at various aspects including aspects of using cheaper substrates (Reddy et al, 2003;Szakacs and Tengerdy, 1997), immobilising enzymes (Woodward, 1989;Dourado et al, 2002), recycling enzymes (Lee et al, 1995) and improvements related to process design (Rivela et al, 2000;Galbe and Zacchi;1993). Although all these latter approaches present opportunities to reduce cost, we will focus on screening for organisms with novel enzymes, strain improvement of existing industrial organisms and enzyme engineering.…”

Enzymatic conversion of lignocellulose into fermentable sugars: challenges and opportunities

“…Th e principle of immobilization is to fi xate the carbohydrolytic enzymes onto a solid matrix either by adsorption or graft ing. 124 Apart from extending the service life of a given enzyme, immobilization will also aff ect activity and stability with regard to temperature and pH optima. Typically broader optima of both pH and temperature are observed.…”