(431c) Effect of Temperature on Pelletizing SPORL Pretreated Forest Biomass and Subsequent Enzymatic Saccharification and Fermentation

Pelletizing of pretreated lignocelluloses to facilitate biomass supply chain logistics was simulated using hot-pressing.  The effects of fiber hornification induced by hot-pressing on enzymatic digestibilities of lodgepople pine and poplar NE222 wood chips pretreated by Sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPROL) were examined.  The pretreated wood chips were pressed at 25ºC, 70ºC, 90ºC, 110ºC, and 177ºC.  The cellulose accessibilities of the pressed and unpressed substrates were evaluated using water retention value and direct cellulase adsorption measurements.  Hot-pressing below 110ºC produced a degree of hornification (DH) below 0.26 and had limited effect on cellulose accessibility and enzymatic digestibility.  Hot-pressing at 177 ºC produced a DH of 0.86 that significantly hornified the fibers and resulted near zero saccharification.  The saccharification results were consistent with cellulose accessibility data.  Ethanol fermentation studies at 18% solids suggest that a pressing below 110ºC is preferred to reduce its effect on biofuel yield.