Enzymes lead the way to sustainable biodiesel

The traditional method of producing biodiesel involves a chemical reaction of an oil feedstock and catalysts like potassium hydroxide and sulfuric acid.

Handling these caustic chemicals is dangerous, and production technicians must wear protective gear at all times during the fuel-making process. A recent breakthrough by Pittsboro, N.C.-based Piedmont Biofuels could change this process, however.

The company has launched commercial production of biodiesel employing a proprietary enzyme catalysis process that it says uses no chemicals and produces no waste.

The announcement marks the first time this process has been used in the U.S.

We recently spoke with Piedmont Biofuels’ co-founder and research director Rachel Burton, who leads the company’s research division, about what this company is doing to make biofuels a greener type of clean energy.

According to Burton, the new process involves two enzymes, which both eliminate waste from either side of the biodiesel reaction. The first one replaces potassium hydroxide and “gets rid of the soap”—a pesky byproduct of traditional biodiesel production. The second one, which has been the focus of Piedmont’s recent research, eliminates the need for sulfuric acid by pre-treating the feedstock with an enzyme called Candida Antarctica Lipase B (CALB).

This process, called Fatty Acid Esterfication using Enzymes, or “FAeSTER,” enables biodiesel producers to make zero-waste fuel from low-quality feedstocks like “yellow grease” (used cooking oil) and “brown grease” (grease that comes out of sewers and restaurant traps).

“These feedstocks are generally considered too degraded to use economically on a commercial scale,” Burton said. “The enzyme catalysts can also be reused—meaning that [producers] can make multiple batches of fuel from the same batch of enzymes.”

Another major benefit is that enzyme catalysis is a much safer production method for the people involved in biodiesel production. “Now, when I make a batch [of biodiesel], I don’t even have to suit up,” Burton said. “It smells like I’m making beer. And, when I spill some on me, it doesn’t burn a hole in my skin.” (ouch!)

The announcement is the culmination of four years of research and collaboration with global enzyme producer Novozymes. Recently, this work has been supported by a Small Business Innovation and Research (SBIR) grant from the U.S. Department of Energy, and a partnership with the Clean Energy Alliance (CEA).

This approach complements Piedmont’s previous work in enhancing the sustainability of U.S. biodiesel production. Globally, critics have questioned the sustainability of transitioning cropland from food to energy crop production, and clear-cutting forests to harvest palm oil for fuel.

Since 2008, Burton has served on the National Biodiesel Board’s Sustainability Task Force, which assesses the U.S. biodiesel industry’s environmental, economic and social sustainability. The task force supports production methods that maximize the fuel’s net energy balance and minimize negative impacts on natural ecosystems. It also identifies and supports business practices that add value, create wealth, and enhance the quality of life for local and global stakeholders.

According to Burton, the industry’s response to their work on enzyme catalysis has so far been positive. Burton was recently named “National Biodiesel Researcher of the Year” by the National Biodiesel Board (NBB). This honor traditionally goes to scientists at national laboratories or universities, but the NBB’s recognition of Burton is testament to the significance of Piedmont Biofuels’ work on enzyme catalysis.

Burton recently presented the FAeSTER process at the 2012 National Biodiesel conference in Orlando, Florida. “There were hundreds of people in our session,” she said. “We also had a booth at the conference, and a lot of people came to visit us after the presentation.” The team plans to use the momentum from the conference to help commercialize the technology with several industry partners in 2012.

The biodiesel industry has been getting a lot of attention lately for producing over 1 billion gallons of fuel last year. According to the NBB, this growth was driven by the EPA’s renewable fuel standard (RFS) and the reinstatement of the $1-per-gallon federal tax credit for biodiesel.

Piedmont Biofuels was recently invited to Capitol Hill to testify on the effectiveness of the RFS; and Burton agreed that the program is essential to sustaining the industry’s growth in 2012 and beyond. “We absolutely need the RFS,” Burton said. “It’s a critical market driver since the lapse of the tax credit.”

* Lauren Craig, EarthTechling