The Pretreatment, Enzymatic Hydrolysis, and Fermentation of Cattails from Constructed Wetlands

Abstract

Using cattails to produce biofuel will add value to the land and will also reduce emissions of greenhouse gases by replacing petroleum products. In order to investigate the feasibility of converting cattails into ethanol, cattails from constructed wetlands on the North Carolina A&T Farm underwent three kinds of pretreatment processes: NaOH, hot water, and dilute sulfuric acid. All three pretreatment methods were able to effectively increase enzymatic digestibility of cattail cellulose. The glucose yields resulting from enzymatic hydrolysis after pretreatment with NaOH, hot water, or dilute sulfuric acid pretreatment were 66.8, 62, and 54.8% of the cellulose (raw cattails basis), respectively. For both dilute sulfuric acid and hot water pretreatment, a high temperature (453–463 K) pretreatment was more effective compared to a lower temperature (394 K) pretreatment. It is recommended that further studies be carried out at a faster heating rate and shorter residence time for the pretreatment process. Saccharomyces cerevisiae (ATCC 24858) and Pichia stipitis (ATCC 58784) were used to ferment the sugars released by cattail cellulose. When using diluted pretreated cattails, both stains were able to ferment glucose to produce similar amounts of ethanol.