Sunday, May 3, 2009
3-09
Pretreatment of Sweetgum (Liquidambar styraciflua L.) with dilute sulfuric acid
Chuan Lau1, Julie Duke1, Elizabeth M. Martin1, Edgar C. Clausen2, Danielle Julie Carrier1, Matthew Pelkki3, and Abigail S. Engelberth2. (1) Biological and Agricultural Engineering, University of Arkansas, Room 203 Engineering Hall, Fayetteville, AR 72701, (2) Ralph E. Martin Department of Chemical Engineering, University of Arkansas, 3202 BELL, Fayetteville, AR 72701, (3) School of Forest Resources, University of Arkansas, Monticello, Arkansas Forest Resources Center, Monticello, AR 71656-3468
The hardwood species Sweetgum (Liquidambar styraciflua L.) grows as understory in pine forests, and is widely distributed in the southeastern United States. Sweetgum trees must be harvested prior to logging of the pine forest, and represent a residue biomass that can be utilized in the production of cellulosic biofuels. In the biochemical conversion platform, the conversion of biomass into liquid fuels is centered on the pretreatment of the biomass, followed by enzymatic hydrolysis of cellulose and hemicellulose, resulting in a C5 and C6 sugar streams that can be anaerobically fermented to ethanol by Saccharomyces cerevisiae, Zymomonas mobilis, Clostridium species or other ethanolgenic microorganisms. Dilute acid pretreatment and saccharification conditions were investigated for sweetgum conversion to monomeric sugars. Sweetgum feedstock was received from UA Monticello and stored at 4°C at UA Fayetteville. The ground feedstock (3.175 mm, 5% solids w/w) was presoaked at room temperature in 0.22%, 0.49% or 0.98% w/w sulfuric acid for at least four hours. Pretreatments were carried out in a 2L Parr reactor heated in a sandbath, and consisted of combinations of 0.22%, 0.49% and 0.98% w/w sulfuric acid at temperatures ranging from 140-200°C for times varying between 5 and 80 minutes. The pretreated slurry was analyzed for monomeric sugar and acid content as described in the National Renewable Energy Laboratory TP-510-42623 protocol.