Ethanol from corn, recently hyped as the nation’s salvation from foreign petroleum, probably isn’t the energy-saving breakthrough many had hoped. Converting corn to ethanol is expensive and
energy-intensive, and by using corn to fuel our vehicles, we take it off the table (and make it far more costly) as a food.
So UC San Diego researchers are looking to develop other biofuels, and delving into surprising realms of green goo and bacteria.
Steve Briggs, a professor of biological science, believes that the current process of using yeast to break down plant matter isn’t nearly as promising as using bacteria for biofuel synthesis. Bacteria grow faster than yeast, and can be engineered to produce complex products such as alkanes and monoterpenes—hydrocarbons and oils that constitute biosynthetic gasoline or diesel.
Briggs’ research has led to the discovery of “TEnBox”—a new control mechanism that dramatically boosts production of biofuels from bacteria. Unlike ethanol, he says, the resulting biogas or diesel offers 100 percent energy density (against ethanol’s 70 percent); it’s noncorrosive, inexpensive, and uses the same sugars (from corn, cane, beets or cellulose) that ethanol production requires.
One of Briggs’ fellow biofuel researchers, Stephen Mayfield, a professor of cell biology at the nearby Scripps Research Institute, has already shown that pond scum can be used to grow human antibodies to fight disease, and now is studying the potential of algae—the humble green slime on ponds—to produce fuel.
That’s not as sci-fi as it sounds, says Suresh Subramani,
professor of biology. The primitive water-based plants, like all plants, use photosynthesis to capture energy and grow. Algae use carbon dioxide from the air as a carbon source and sunlight as
an energy source, so huge ponds of algae can be grown relatively inexpensively.
Properly treated, algae can produce oils, which can be used
as fuels. Bioengineering the algae can streamline the process — and Subramani says that algae can be grown on otherwise unproductive land, needing little more than space, a bit of water and sunshine. And because algae absorb carbon dioxide, they serve as carbon-sequestration resources as well.
A society fueled on pond scum? Stay tuned.
— Paul K. Mueller
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