Methods and systems for collecting, purifying, and/or extracting ethanol produced during anaerobic metabolism by aquatic plants is provided. The system includes a cell containing water and an aquatic plant, an ethanol extraction assembly in fluid communication with the cell for removing ethanol from the water. Ethanol is released by the aquatic plant by initiating an anaerobic process in the plant such as by regulating the photosynthesis inducing light that reaches the aquatic plant.