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Alternative fuel of the 21st century goes green

December 04, 2006

As anyone with a pool knows, algae can be quite pesky plants. While it’s not desirable to have it growing in your pool, ASU researchers Qiang Hu and Milton Sommerfeld are shedding a whole new light on the plant in the Laboratory for Algae Research & Biotechnology (LARB) at the Polytechnic campus.

Even though algae can be a nuisance, these plants have multiple benefits to the environment that are sustainable, renewable and relatively inexpensive to produce. Algae have properties that make them great for many applications, according to Hu and Sommerfeld.

The duo has been able to take their combined 40-plus years of research with algae and apply it to use in air and water remediation, alternative fuels and animal feed. During that time, they have identified 100 to 200 algal species of the more than 1,500 they have studied that are hardy and potent for various uses from producing algal oils for biofuels to removing carbon dioxide from power plant emissions and nutrients from various wastewaters.

What makes algae so appealing for so many applications?

“They reproduce quickly, and unlike the cells found in a leaf, they don’t have unnecessary baggage. In other words, no roots and stems and they do not go dormant,” says Sommerfeld. “Algae have natural properties that allow them to grow quickly, with some species able to double 2 to 3 times in a day. That’s a good thing when you want to produce large quantities of algae.”

To grow mass quantities of algae, the researchers developed industrial photobioreactor technology that allows for an optimal growth environment for maximum production, according to Hu. “It’s basically an engineered device to enhance the natural process,” adds Sommerfeld.

What the plant and its cells are naturally producing makes them a valuable product, according to Hu. “For example, we have been able to identify one species of algae that synthesizes and accumulates large quantities of oils or lipids that could be a perfect alternative fuel for airplanes/jets because it releases far less air pollutants than petroleum-based fuels into the atmosphere,” says Hu.

The byproduct from harvesting the oil makes a healthy animal feed product or organic fertilizer as well. Through an anaerobic digestion or fermentation process, the byproduct can also be converted to methane or ethanol -- two other kinds of biofuels. So there is little waste associated with algal feedstock.

In addition to the use of the oil lipids, their research has been successful at removing waste nutrients from agricultural wastewaters through an algal filtration system, allowing for reuse of treated water. Currently they are applying the technology to other sources of wastewater, such as nitrate-contaminated groundwater, municipal wastewater and concentrated animal feeding operation wastewater. These research and development projects have been supported by the local industrial community, including Salt River Project and Arizona Public Service, along with state and federal grants.

The pair has 10 patent applications pending, and their work is attracting the attention of industry for commercialization purposes.

“Our algae-based biofuel technology is at a field pilot-scale demonstration stage and it is anticipated that it could reach the marketplace within three to four years,” says Hu.