Wednesday, May 6, 2009 - 3:00 PM
12-04

Effects of Chemical Pretreatment on Enzymatic Hydrolysis of Lignocellulose Observed by AFM

Hao Liu, State Key Laboratory of Pulp and Paper Engineering, South China Univeristy of Technology, 381 Wusha Road, Guangzhou, 510640, China, Wenyuan Zhu, State Key Laboratory of Pulp and Paper Engineering, South China University of Science and Technology, Guangzhou, J. Y. Zhu, USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Dr, Madison, WI 53726, and Shiyu Fu, State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou.

Lignocellulsoe has natural resistance to microbial and enzyme destruction often called “recalcitrance”.  The recalcitrance of lignocellulose is a major barrier to the economical development of biobased fuels and chemicals.  Chemical pretreatment is often applied to biomass feedstock to remove lignocellulose recalcitrance for efficient subsequent enzymatic saccharification.  The performances of different chemical pretreatments vary significantly. Understanding of the fundamentals of nano-scale phenomena on lignocellulsoe substrate during enzyme actions can provide insight about why some pretreatment is more effective than others. This understanding can lead to developing efficient pretreatment processes and enzyme systems to improve lignocellulose bioconversion.  This presentation will provide some observations of the effects of chemical pretreatment on enzymatic hydrolysis of lignocellulose substrate using AFM.  Dilute acid, hot water, and SPORL pretreatment were applied to lodgepole pine and eucalyptus wood chips to produce substrates.  Enzymatic hydrolysis of the pretreated substrates was conducted at 50oC with enzyme loading of 15 FPU/g substrate od solid.  AFM imaging was applied to substrates after enzyme actions for various incubation duration times.  The AFM images clearly showed the enzymes attached to the substrate and the destruction of celluloses microfibriles over time after enzyme actions.  Furthermore, the effect of CBD on enzyme attachement can be clearly seen from the AFM images.  The effects of pretreatment process on the dynamics of nano-scale enzyme destruction of lignocellulose can be cleary seen.  When correlating the AFM imaging information with time-dependent quantitative enzymatic cellulose conversion data, the effects of nano-scale enzyme process on macro-scale cellulose conversion can be easily understood.

 


See more of Biomass Recalcitrance
See more of The 31st Symposium on Biotechnology for Fuels and Chemicals (May 3-6, 2009)