The Effects of Potassium Hydroxide on the pH Levels During the Growth and Fermentation of Lemna minor

The purpose of this experiment was to determine how potassium hydroxide (KOH) affects the pH levels of the habitat in which Lemna minor, or common duckweed, grows in and how it consequently alters the pH levels while the plant is fermenting. It was hypothesized that the trial that added the most potassium hydroxide to the habitat would produce a fermentation mixture with the most stable pH level and create the most ethanol. This experiment included adding different levels of KOH to four containers that common duckweed grew in for one week. KOH was added in the hopes of stabilizing the pH level during fermentation. The pH levels were monitored while the plants grew and were found to range from 6 to 9 which is the range the plant grows best in. The duckweed was then fermented for another week and again the pH levels were monitored. During fermentation, the levels gradually rose from 4.5 to 6.5 but the medium trial was found to produce the most ethanol and stayed in the optimum range between 4.5 and 5.5 longer than any other trial. The increase of carbon emissions from the burning of fossil fuels is causing a greater need for eco-friendly options to power cars. Recently, biofuel made from plant-based ethanol has been popularized and investigated as a “greener” way to run automobiles. Corn is mainly used in the production of biofuel but growing and harvesting it is not cost efficient. However, duckweed has shown great potential in producing equal amounts of biofuel at a fraction of the cost.

Research Conducted By:

Matthew Fuhrman
Clintondale High School

Elise Tomaszewski
Lake Shore High School