Alkali Pretreatment and Enzymatic Hydrolysis of Cattails from Constructed Wetlands

Problem statement: To date, production of liquid fuel, particularly et hanol, has only been economically feasible from food crops that are high in sugar and starch. However, the use of arable land for fuel rather than for food production and t he use of a food source for fuel rather than as foo d have created issues in prices and availability of t raditional foods and feed. The use of cattails to produce biofuel will add value to land and will als o reduce emissions of greenhouse gases by replacing petroleum products. Approach: In order to investigate the feasibility of converti ng cattails into cellulosic ethanol, an alkali (NaOH) pretreatment p rocess was studied using cattails from constructed wetlands on a North Carolina A and T Farm based on NaOH concentration and enzyme loading. Results: The alkali pretreatment method was able to effecti vely increase enzymatic digestibility of cattail cellulose; nearly 78% of the cellulose from raw cattails was converted to fermentable glucose in 48 h using a cellulase loading of 60 FPU g -1 glucan. About 25.5, 37.4, 38.4, 42.4 and 55.9% of the lignin was removed with pretreatment in 0.5, 1, 2, 3 and 4% NaOH, respectively. The yeast Saccharomyces cerevisiae (ATCC 24858) was able to ferment the sugars released by cattail cellulose. Conclusion: The overall effectiveness of alkali pretreatment w as a function of NaOH concentration and enzyme loading. NaOH concentrations in the range of 1-2% are recommended for the pretreatment of cattails. For cattails pretreated with 4% NaOH, no significant change in digestibility occurred whe n enzyme loading was increased beyond 15 FPU g -1 glucan. It is recommended that further studies be carried out using cattails as a feedstock for biofu els, especially to optimize the economics of pretreatment processes for cattails in terms of ene rgy input, enzyme loading, glucose yield and xylose yield.