Ethanol From Potato, Sweet potato and Taro

A Comparative study on Ethanol content from potato, sweet potato and taro was conducted by Research II students of the University of the Philippines High School in Cebu. The said study was conducted by Mariel Stephanie Alvizo, Juna Rose Dinglasa, John Albert Metoda and Doanne Lyre Montecastro.Here is a summary of the study.
Our country mainly depends on foreign products like energy from oil and petroleum. We get most of these from the Middle East. We are directly affected with the increasing rates of these energy sources especially that we experience inflation here in the Philippines. People have come up with ideas of using alternatives for petroleum; alternatives that are cheaper than but still as good as petroleum. Then biodiesel came up. Biodiesel refers to a diesel-equivalent, processed fuel derived from biological sources (such as vegetable oils), which can be used in unmodified diesel-engined vehicles. One of the raw materials needed to make biodiesel is ethyl alcohol commonly known as ethanol. Ethanol is found in starchy and sugary plants. The plants used in this project are under those which are starchy. These plants are the root crops potato, sweet potato and taro (commonly known as gabi). The researchers also used decided to use these root crops because of its availability in Cebu. This project aims to measure the ethanol content in the three root crops. These root crops were boiled, mashed then blended separately. Yeast was added to the blended root crops. The root crops underwent the process of fermentation for 30 days. Fermentation is the conversion of sugar to alcohol using yeast under anaerobic conditions. A more general definition of fermentation is the chemical conversion of carbohydrates into alcohols and acids. After the fermentation process, the fermented root crops were subjected for distillation which is the process of separating liquid from another liquid. Ethanol must be separated from water at this rate. When evaporating, the temperature must not exceed 80 degrees Celsius because if it does exceed, it will become water. This process took the researchers 15 hours per root crop. The gathered samples are contained in a Florence flask. To test if the gathered samples are really ethanol, the researchers used the flame test. A thimbleful of the sample was lit to see if it really was ethanol. Sweet potato showed a bigger spark than potato while taro didn’t spark at all.
In the first trial, ethanol gathered from 100 ml of sweet potato was 7.9 ml, 0.8 ml from potato and 1.5 ml from taro respectively.
In trial 2, the volume of ethanol extracted from 100 ml of sweet potato was 7.1 ml, from potato was 8.6 ml and from taro was 9.5 ml. The mean volume of ethanol content from sweet potato is 7.5 ml; 4.7 ml from potato and 5.5 ml from taro. From the results, the researchers concluded that sweet potatoes yielded the greatest amount of ethanol and that it is the best source of ethanol among the three root crops. And from these conclusions, the researchers came up with recommendations like the promotion of biodiesel as an alternative for petroleum for sectors like the Department of Agriculture and the Department of Science and Technology. They also recommended the establishments of companies that allow the production of ethanol to the investors. And lastly, they recommend the improvement of the study to the future researchers.