270192 Chemical Pretreatment and Fermentation of Water Hyacinth (Eichhornia crassipes) At Its Optimum Age

Wednesday, October 31, 2012: 10:35 AM
303 (Convention Center )
Alvin R. Caparanga, School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila, Philippines and Jan-Ray M. Oxales, School of Chemical Engineering and Chemistry, Manila, Philippines

Water hyacinth (Eichhornia crassipes) is an aquatic plant that has been considered an environmental nuisance. But, this lignocellulosic biomass can be a good substrate for ethanol production. The average life-span of this plant is 25 days. In this study, we determined the age at which the plant’s holocelulose (cellulose + hemicelluloses) is highest and its lignin lowest. We found out that a 5-day old plant has the highest holocellulose-to-lignin ratio. We pretreated the 5-day-old plant samples with different chemicals (H2SO4, NaOH, H2O2) at 121 °C and 60 psia for 1 h to convert hollocellulose into fermentable sugars. We also followed the changes in lignin, glucan and xylan contents of the treated plant samples. The NaOH-treated samples had the highest level of delignification (63.32 %) and highest cellulose to glucose conversion (68.00 %). The H2SO4-treated samples had the highest xylan reduction (74.65 %) but lowest cellulose to glucose conversion (38.58 %). The H2O2-treated samples had the lowest delignification (30.43 %) although its cellulose to glucose conversion was 59.57 %. Using a traditional strain of Saccharomyces cerevisiae, we fermented the hydrolyzed samples and produced 13.63 g ethanol per liter (0.16 g ethanol per g dry biomass) for the NaOH-treated sample, 8.13 g ethanol per liter (0.13 g ethanol per g dry biomass) for the H2SO4-treated sample, and 9.32 g ethanol per liter (0.14 g ethanol per g dry biomass). These yields are either better or near-equal to those reported for same biomass and other agricultural biomass.

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