(167b) Zeta Potential of Lignin Plays a Positive Role in the Enzymatic Hydrolysis of Woody Biomass

Authors: 
Tu, M., Auburn University
Huang, Y., Auburn University

The zeta potential related electrostatic interactions play a critical role in enzymatic hydrolysis of lignocellulsoic biomass. The objective of our study was to elucidate the positive effects of organosolv lignins on enzymatic hydrolysis.  We observed the positive effects of organosolv lignins (EOL-CW, EOL-SG, EOL-BW and EOL-AS) from cottonwood, sweetgum, black willow and aspen) on enzymatic hydrolysis. On the contrary, we observed the negative effects of EOL-EH and EOL-LP from Eucalyptus and Loblolly pine on enzymatic hydrolysis.  The addition of EOL-CW, EOL-BW and EOL-AS improved the 72 h hydrolysis yields of Avicel from 61% to 68%, 65% and 63%, respectively. The addition of EOL-EH and EOL-LP decreased the 72 h hydrolysis yields of Avicel to 53% and 56%, respectively. A good correlation between the zeta potentials of lignin and the hydrolysis yields indicated that the positive effects of organosolv lignins on enzymatic hydrolysis were governed by the zeta potential. The different zeta potential of lignin probably was related to the surface charges and hydrophobicity of lignin, which were further controlled by the physical and chemical properties of lignin. Our study suggested that organosolv lignins with high zeta potentials (>10 mV) could enhance enzymatic hydrolysis.