Thursday, May 3, 2012: 3:30 PM
Waterbury Ballroom, 2nd fl (Sheraton New Orleans)
Cellulosic ethanol is expected to be commercialised and partially replace first generation ethanol in the near future. However, cellulosic ethanol is still not economically viable without governmental subsidies. Enzymes required for total hydrolysis form one of the major operation cost factors in the conversion of lignocellulosic raw materials to sugars and further to ethanol. Hence, efficient recycling of enzymes or major enzyme components could clearly reduce enzyme costs in total hydrolysis of lignocellulose. Providing enzymes suitable for recycling would accelerate the development of the approaching cellulose-to-ethanol industry. Currently, enzyme recycling is, however, hindered by the lack of easily recyclable enzymes and suitable technology for enzyme recycling.
After the hydrolysis of common lignocellulosic substrates, a significant part of the enzymes remains bound to the residual cellulose and/or lignin of the biomass, and is poorly desorbed by chemical or physical means without losing enzymatic activity. In this work, cellulolytic enzymes and hydrolysis conditions were modified to facilitate enzyme recycling. These modifications resulted in a significantly higher amount of free enzymes at the end of the hydrolysis. The amount of recoverable enzymes in the liquid phase was increased to about 60-90% of the originally loaded enzyme. This work describes a possible way to develop enzyme mixtures with increased recyclability without compromising the hydrolysis efficiency.