%0 Journal Article
%T Cellulase recycling after high-solids simultaneous saccharification and fermentation of combined pretreated corncob
%A Ruoyu Du
%A Rongxin Su
%A Wei Qi
%J Frontiers in Energy Research
%D 2014
%I Frontiers Media
%R 10.3389/fenrg.2014.00024
%X Despite the advantageous prospect of second-generation bioethanol, its final commercialization must overcome the primary cost impediment due to enzyme assumption. To solve this problem, this work achieves high-concentration ethanol fermentation and multi-round cellulase recycling through process integration. The optimal time and temperature of the re-adsorption process were determined by monitoring the adsorption kinetics of cellulases. Both glucose and cellobiose inhibited cellulase adsorption. After 96 h of ethanol fermentation, 40% of the initial cellulase remained in the broth, from which 62.5% of the cellulase can be recycled and reused in fresh substrate re-adsorption for 90 min. Under optimum conditions, i.e., pH 5.0, dry matter loading of 15 wt%, cellulase loading of 45 FPU/g glucan, two cycles of fermentation and re-adsorption can yield two-fold increased ethanol outputs and reduce enzyme costs by over 50%. The ethanol concentration in each cycle can be achieved at levels greater than 40 g/L.
%K Cellulase
%K Lignocellulose
%K Enzyme recycling
%K High-solids
%K Simultaneous saccharification and fermentation (SSF)
%U http://www.frontiersin.org/Journal/10.3389/fenrg.2014.00024/abstract