(62b) Evaluation of Pretreatment Methods In the Production of Ethanol From Cattail Leaves

Previous research in this lab indicated that cattails are a potential source of biomass for the production of cellulosic ethanol since their carbohydrate composition is comparable to that of other plants being considered for biofuel production. To further test their viability, we tested various pretreatment methods on dried cattail leaves. Before polysaccharides in plants can be enzymatically hydrolyzed to fermentable sugars, the plant material must be pretreated to render the polysaccharides accessible to the enzymes. The purpose of this project has been to compare the efficiency of sulfuric acid and ammonia pretreatment methods in preparing cattail biomass for ethanol production. In this project, dried, powdered cattail leaves were pretreated either by autoclaving them with 2% sulfuric acid for one hour or by incubating them overnight at 40 C° in 15 % aqueous ammonia. Samples of the dried, pretreated solid were treated with cellulase and -glucosidase for 48 hours. To compare the efficiency of these pretreatment methods, glucose liberated in these samples was measured by a glucose oxidase assay. It was found that more glucose was recovered in the enzymatic hydrolysis (step two) than in the pretreatment step (step one.) In step two, more glucose was liberated from biomass pretreated with ammonia than from biomass pretreated with sulfuric acid. However, more glucose was recovered from in step one by sulfuric acid pretreatment. Overall 27.8 % of the starting biomass was recovered as glucose with ammonia pretreatment compared to 11.7 % for sulfuric acid pretreatment. Interestingly, 22.3% of the starting biomass was recovered as glucose when no pretreatment was used.