Characterization of Fall Leaves as a Source of Cellulosic Ethanol

Abstract

Ethanol is becoming increasingly popular as a fossil fuel additive or substitute. However, current production of ethanol from corn impacts food prices and appears to have an overall low net yield. New sources need to be identified and new processes developed for ethanol production. Cellulosic ethanol is one such new source. Plant material contains a large amount of cellulose and other polysaccharides which are potential feed stocks for ethanol production. The purpose of this experiment was to characterize the polysaccharide, lignin, and ash content of fall leaves to estimate their potential for ethanol production. A slight modification of the NREL procedure “Determination of Structural Carbohydrates and Lignin in Biomass” was used to characterize the leaves. Results of this analysis demonstrated that the leaves were composed of cellulose (23.8 +/- 1.6%), xylan (7.4+/- 0.7%), arabinan (7.9+/-0.8%), acid soluble lignin (22.3+/- 1.0%), acid insoluble lignin (27.6%), and acid insoluble ash (2.6%). It is estimated that approximately 60 gallons of ethanol could be produced per ton of leaf litter. In comparison to other cellulose sources, leaf litter has less sugars and will produce less ethanol. However, energy is already being expended to harvest leaf litter whereas addition energy would be consumed to harvest other cellulose sources.