Algae biofuel is an alternative to fossil fuel that uses algae as its source. Several companies and government agencies are funding efforts to reduce capital and operating costs and make algae fuel production commercially viable. Taking an approach similar to that used for discovering new therapeutic drugs, chemists at the University of California, Davis, have found several compounds that can boost oil production by green microscopic algae, a potential source of biodiesel and other green fuels. The work appears online in the journal Chemical Biology. Microalgae are single-celled organisms that, like green plants, use photosynthesis to capture carbon dioxide and turn it into complex compounds, including oils and lipids. Marine algae species can be raised in saltwater ponds and so do not compete with food crops for land or fresh water.
Harvested algae, like fossil fuel, releases CO2 when burnt but unlike fossil fuel the CO2 is taken out of the atmosphere by the growing of algae. Among algal fuels attractive characteristics: they can be grown with minimal impact on fresh water resources, can be produced using ocean and waste water, and are biodegradable and relatively harmless to the environment if spilled. The problem is capital cost and yield to make it economic.
"They can live in saltwater, they take sunlight and carbon dioxide as a building block, and make these long chains of oil that can be converted to biodiesel," said Annaliese Franz, assistant professor of chemistry and an author of the paper.
Franz, graduate students Megan Danielewicz, Diana Wong and Lisa Anderson, and undergraduate student Jordan Boothe screened 83 compounds for their effects on growth and oil production in four strains of microalgae. They identified several that could boost oil production by up to 85 percent, without decreasing growth.
Among the promising compounds were common antioxidants such as epigallocatechin gallate, found in green tea, and butylated hydroxyanisole (BHA), a common food preservative.
The team has carried out growth experiments in culture volumes of up to half a liter. They calculate that some of the chemicals they analyzed would be cost-effective when scaled up to a 50,000 liter pond. After oils have been extracted from the algae, the remaining mass can be processed for animal feed or other uses.
The idea, Franz said, is to look for small molecules that can affect a metabolic pathway in a cell. By setting up large numbers of cell cultures and measuring a simple readout in each, it's possible to screen for large numbers of different compounds in a short time and home in on the most promising.
"The basic concept comes from the pharmaceutical industry, and it's been used for human cells, plants, yeast, but not so far for algae," she said.
"There are many cases where small molecules are having an effect to treat a disease, so it makes sense that if you can affect a pathway in a human for a disease, you can affect a pathway in an algal cell," Franz said.
For further information see Algal Oil.
Algal Fuel image via Wikipedia