4-27: Saccharification of yellow poplar using supercritical water for the second generation bioethanol

   A single step hydrolysis of lignocellulosics using a supercritical water system has studied to develop a simple and rapid saccharification method that will be applied to second generation bioethanol production. In conventional saccharification process of lignocellulosics, monomeric sugars can be obtained in a long time process through multiple reaction steps such as separation of cellulose fibers and hydrolysis of the cellulose fibers. For the second generation bioethanol, these pretreatment and hydrolysis processes are the main cause of high cost of production. For reduction of the cost of production and commercialization, cost-effective saccharification process is needed.

In this study, wood powder of Yellow poplar (Liriodendron tulipifera) was treated in a supercritical water system equipped with a flow-type reactor at 380, 400, and 425℃ under the pressure of 23 MPa. Wood powder (10 g) was suspended in 1 L distilled water mixed with 0.05 % HCl before the reaction. The suspension was pumped into the reaction tube at a speed of 100 mL/min. Our results indicate that above 40 % of cellulose 60 % of hemicellulose in wood could be hydrolyzed and existed in monomeric sugar form. As a conclusion, this simple and rapid thermochemical saccharification process of lignocellulosics can be suggested as a cost-effective process for production of the second generation bioethanol.