Researchers Tap Papaya-Loving Algae to Make “Home-Grown” Biodiesel for Hawaii

by Jan Suszkiw (U.S. Department of Agriculture) ... In Hilo, Hawaii, Agricultural Research Service (ARS) Plant Pathologist Lisa Keith is leading an effort to produce biodiesel using a type of green algae known as Auxenochlorella protothecoides (formerly Chlorella protothecoides).

Oh, and she’s also using the pulp of discarded papayas, namely, those deemed too blemished, malformed, or damaged to be sold for market.

The system devised by Keith and her colleagues calls for growing the algae in giant vats, called “bioreactors.” There, hidden from sunlight, the algae are fed what might be likened to a papaya smoothie.

“While nearly all algae are capable of using energy from light to produce organic molecules from carbon dioxide and water, some algae, including Auxenochlorella protothecoides, can also absorb organic molecules such as sugars from sources such as papaya juice,” explains Keith. She is with ARS’s Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center in Hilo.

In the process, these industrious algae end up storing 60 percent of their cellular weight in lipids. These lipids (or oils), in turn, provide material for making biodiesel. READ MORE