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Microscopic diatoms like the one shown above could yield massive amounts of oil, scientists say. Credit: The American Chemical Society

Scientists in Canada and India are proposing a surprising new solution to the global energy crisis —“milking” oil from the tiny, single-cell algae known as diatoms, renowned for their intricate, beautifully sculpted shells that resemble fine lacework. Their report appears online in the current issue of the ACS’ bi-monthly journal Industrial Engineering & Chemical Research.

Richard Gordon, T. V. Ramachandra, Durga Madhab Mahapatra, and Karthick Band note that some geologists believe that much of the world’s crude oil originated in diatoms, which produce an oily substance in their bodies. Barely one-third of a strand of hair in diameter, diatoms flourish in enormous numbers in oceans and other water sources. They die, drift to the seafloor, and deposit their shells and oil into the sediments. Estimates suggest that live diatoms could make 10−200 times as much oil per acre of cultivated area compared to oil seeds, Gordon says.

“We propose ways of harvesting oil from diatoms, using biochemical engineering and also a new solar panel approach that utilizes genetically modifiable aspects of diatom biology, offering the prospect of “milking” diatoms for sustainable energy by altering them to actively secrete oil products,” the scientists say. “Secretion by and milking of diatoms may provide a way around the puzzle of how to make algae that both grow quickly and have a very high oil content.”

“We have been charged to develop the next generation of cellulosic biofuels. When we successfully supply sources of energy to the grid from non-food, cellulosic, parts of plants we will mitigate the food versus fuel debate,” says Tim Donohue of the University of Wisconsin, Madison, one of two directors of Department of Energy Bioenergy Research Centers who spoke today in a session at the meeting.
When it comes to alternative fuels, currently ethanol is king. Almost all ethanol produced in the United States is fermented from readily available sugars in corn starch or corn kernels. Producing ethanol from corn has also come under much criticism lately, accused of being responsible for rising food prices.

Researchers are looking at alternate biomasses as food for microorganisms to ferment into ethanol. The most attractive are known as lignocellulosic biomass and include wood residues (including sawmill and paper mill discards), municipal paper waste, agricultural residues (including sugarcane bagasse), dedicated energy crops (like switchgrass) or the non-edible parts of corn like cobs, stalks or stover. The problem is, unlike corn starch, the sugars necessary for fermentation are trapped inside the lignocellulose part of this plant biomass. The key to ending the food versus fuel debate is unlocking the sugars trapped in cellulosic biomass.

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, Bioufuel research and development, South San Francisco