(370f) Effects of the Pretreatment Processes of Grassy Biomass Grown for Soil Remediation and Biofuel Production

Biomass is the only renewable source of organic carbon that, when utilized efficiently and optimally, can significantly reduce our present reliance on fossil fuels and, thus reduce the emissions of green house gases from these non-renewable materials.  Lignocellulosic biomass is abundant, does not compete with the production of food crops, and considered relatively inexpensive. However, the complex nature of biomass and many ill-defined issues related to biomass utilization pose a substantial challenge to the large-scale biomass utilization.  Growing biomass for energy crops, such as switchgrass, means that more land needs to be utilized. It is desired that biomass for energy crops to be grown in land area that is considered marginal. 

At Villanova University, we are working on to develop a sustainable processing system for producing biofuels from grassy plants that can be grown on heavy-metal contaminated soils in underutilized areas such as superfund sites. Certain types of perennial grasses, such as switchgrass and timothy grass, may have great potential for improving the quality of heavy metal contaminated soil by taking up the heavy metal contaminant from the soil and subsequent removal by repeatedly harvesting the above-ground biomass.  These grasses also have great potential to be used as bio-renewable feedstock for the production of bionergy and biofuels due to their relatively high yields of biomass per acreage of land. On the biomass conversion processes, the  focus of the study is on utilizing switchgrass and timothy grasses that is grown in the soil that has been purposely contaminated with lead for their potential as feedstock for biofuel production using a hybrid biochemical and thermochemical approaches, i.e. fermentation and fast pyrolysis. To be reported in this paper is a part of the study in which we are pretreated the lignocellulosic materials in order to optimize the utilization of carbon in the biomass.   Lignocellulosic materials consist of cellulose, hemicelluloses and lignin; these three components are strongly bound together which make it difficult to utilize this type of biomass in the production of biofuels on a commercially viable scale. We hypothesize that optimal utilization of carbon is to be done by first converting cellulose into sugars which subsequently fermented to produce ethanol. In the second step, the remaining solid biomass (containing primarily lignin) is pyrolyzed to produce bio-crude oil. Low acid hydrolysis was applied with the intention of disrupting the structure of the biomass by breaking in order to allow enzyme to penetrate the biomass structures more to increase the sugar yields from cellulose during enzymatic treatment.

To be reported in this presentation are the results obtained from the treatment on switchgrass and timothy grass by dilute acid hydrolysis followed by enzymatic hydrolysis.  The effects of acid hydrolysis to the sugar yield and the composition of the remaining solids from enzymatic treatment are evaluated. To be reported also is the effect of lead contained in the grasses.