Impact of surfactants on pretreatment of corn stover.

Center for Environmental Research and Technology, Chemical and Environmental Engineering Department, Bourns College of Engineering, University of California, 1084 Columbia Avenue, Riverside, CA 92507, USA.
Bioresource Technology (Impact Factor: 5.04). 03/2010; 101(15):5941-51. DOI: 10.1016/j.biortech.2010.03.003
Source: PubMed

ABSTRACT Lignin in pretreated cellulosic biomass can non-productively adsorb cellulase, resulting in loss of a significant portion of this expensive protein. In addition, lignin interferes with the path for cellulase action, slowing down hydrolysis. Thus, the effectiveness of enzymatic hydrolysis of pretreated lignocellulosic biomass can be significantly enhanced if lignin is removed or effectively modified before adding enzymes. In this study, the enzymatic digestibilities of solids resulting from using the surfactants Tween-80, dodecylbenzene sulfonic acid, and polyethylene glycol 4000 during water-only or dilute acid pretreatment of corn stover at 140-220 degrees C were evaluated. All of these surfactants increased lignin removal during pretreatment and reduced non-productive binding of enzymes on the biomass surface, but Tween-80 increased enzymatic hydrolysis yields and enhanced total sugar recovery more than the other two. Surfactant pretreatment was found to improve lignin solubility, which could improve cellulose digestibility by reducing unproductive binding to enzyme, and also appeared to enhance performance by modifying the biomass surface.

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    ABSTRACT: Addition of additives has been confirmed to increase cellulase performance in the hydrolysis of lignocellulosic materials. In the hydrolysis of xylan-containing lignocellulosic biomass, xylanase can synergistically enhance the performance of cellulase. However, the role of additives in xylan hydrolysis by xylanase is not yet clear. In this work, with the presence of additives (bovine serum albumin, poly(ethylene glycol), and Tween), the hydrolysis of isolated xylan and the xylan in corn stover increased to different extents. Additives increased free xylanase in supernatants in the hydrolysis with xylanase, indicating the reduction of the adsorption of xylanase on corn stover and insoluble xylan. Enhanced hydrolysis of Avicel and corn stover by additives suggested that besides the prevention of unproductive binding of xylanase to lignin by additives, reducing the adsorption of xylanase on substrates was also contributed to enzymatic hydrolysis. The increment of xylanase activity by additives suggests that the additives were activators of xylanase. The results of this work indicate that the supplementation of additives could improve xylanase performance, synergistically enhanced the cellulose hydrolysis, and beneficial for the recycling of xylanase.
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