Cellulase immobilized by sol–gel entrapment for efficient hydrolysis of cellulose

Abstract

Cellulase from Trichoderma reesei (Celluclast 1.5 L, Novozyme) was immobilized by sol-gel encapsulation, using binary or ternary mixtures of tetramethoxysilane (TMOS) with alkyl- or aryl-substituted trimethoxysilanes as precursors. Optimization of immobilization conditions resulted in 92 % recovery of total enzymatic activity in the best immobilized preparate. The immobilized cellulase exhibiting the highest activity, obtained from tetramethoxysilane and methyltrimethoxysilane precursors at 3:1 molar ratio, was investigated in the hydrolysis reaction of microcrystalline cellulose (Avicel PH101). Although the optimal values did not change significantly, both temperature and pH stabilities of the sol-gel entrapped cellulase improved compared to the native enzyme. Immobilization also conferred superior resistance against the inactivation effect of glucose. Reuse of the sol-gel entrapped cellulase showed 40 % retention of the initial activity after five batch hydrolysis cycles, demonstrating the potential of this biocatalyst for large-scale application.

Tailored sol–gel immobilized lipase preparates for the enzymatic kinetic resolution of heteroaromatic alcohols in batch and continuous flow systems

“…Consequently, this biocatalyst might not be a suitable candidate for repeated use. Biocatalysts obtained through sol-gel entrapment, on the other hand, do not have this disadvantage and have proved in our previous work 27,35,38 and in other studies 11,15,39 remarkable recycling stability. …”

“…35 The combined method of sol-gel entrapment and adsorption was also carried out as described elsewhere.…”

Modeling the Effect of pH and Temperature for Cellulases Immobilized on Enzymogel Nanoparticles

“…The model for cellulase (protein) recovery (R CE ) after hydrolysis with cellulase enzymogel is shown in Eq. (6). The respective ANOVA table for the model is shown in Table 5.…”

“…Recovering and reusing cellulase enzymes has been identified as one method of lowering production costs of cellulosic biofuel [3]. Cellulases have been immobilized on supports such porous silica particles [4], polyacrylate copolymers [5], or by sol-gel encapsulation [6]. Efficacy of free and immobilized cellulase was compared for individual variables such as pH and temperature; however, parameter interactions were not modeled for their effect on recovery and efficacy.…”

Hydrolysis of Cellulose by Immobilized Cellulase in a Packed Bed Reactor

“…고정화 효소를 사용하면 안정성이 높고 재사 용이 가능하기 때문에 전체 공정의 비용을 줄일 수 있다. 고정 화 방법으로는 가두기(entrapment)에 의한 방법 [5,27], 담체로 키토산과 PVA을 사용하는 방법 [6,14,18], 가교에 의한 공유 결합 방법 [9], 실리카 겔과 같은 무기물이나 polyacrylamide와 같이 고분자에 의한 고정화 방법 [22,29] 등이 있다. 효소 고정 화의 단점인 기질의 물질전달에 의한 확산 저항을 감소시키기 위한 연구도 진행되었다 [1,26].…”