An Insight into the Production of Bioethanol from the Duckweed

Tsgehiwet Gebremichal Hailu; Gebreyohannes Gebrehiwot

Abstract

The ultimate goal of this study was provided an insight into the production of bioethanol from the duckweed. In this study three experimental parameters for maximizing bioethanol yield were investigated during the dilute acid hydrolysis; acid concentration (0.6-1M), temperature (80-120oC) and time (60-180minutes). The conversion of duckweed to bioethanol can be achieved mainly by four process step; the first step was pretreatment of duckweed to remove different contaminates, dried at 60°C for 24hr and ground to the particle size of 2 mm. The pretreated duckweed was soaking in diluted acid hydrolysis to convert the starch into simple sugar. The simple sugars were fermented using Saccharomyces cerevisiae in anaerobic condition at 30°C, 4.5-5.3pH and 72hours, and the residual solutions were distilled every 150minutes by rotary evaporator. The concentrations of bioethanol were measured by Alcoholmeter and Pycnometer. Response Surface Methodology (RSM) using Design expert® 7.0 was used to optimize the bioethanol yield. The optimum result was obtained at 0.8M acid concentration, 100oC and 120minutes. The yield of bioethanol is 4.57ml/20gm (0.18gm/gm) was achieved under these conditions. The minimum result showed that bioethanol yield of 4.33/20gm sample (0.17gm/gm) was obtained at 0.91M, 103.59oC and 165 minutes respectively. Generally, the production of bioethanol from duckweed could be an option for energy and other uses.

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