Immobilization on Nanoparticles
Cellulases immobilized on silica nanoparticles by physisorption mechanisms have been used to study the effect of immobilization on a simultaneous saccharification fermentation (SSF) experiment. In this study, Lupoi et al. compared immobilized cellulases to enzymes in solution. They found that cellulase adsorbed to 40 nm silica nanoparticles produced 1.6 times more glucose than cellulase in solution after 96 h at pH 4.8 and at 35°C. There was no significant accumulation (< 250pg) of soluble cellooligomers in either the solution or immobilized enzyme reactions. The results showed that silica immobilized cellulases can be used to produce increased ethanol yields in the conversion of lignocellulosic materials to ethanol by SSF [64].
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Figure 6.6 Reusability of immobilized cellulase for hydrolysis of corn stover. Reactions were carried out in acetate buffer (100 mM, pH = 5.0) at 50°C. Relative activities were calculated by using the first time activity of immobilized cellulase as 100%. (Reprinted with permission from reference [50]; copyright 2012 Elsevier). |