Most biofuel production in the United States relies on growing corn as feedstock. That method has been criticized as being energy-inefficient and for driving up the price of food, among other issues. Using oils from algae to produce biofuels has received a lot of attention as an alternative, but even there, researchers have struggled to make the process economically viable.
But now scientists in the Department of Chemical and Biological Engineering at the University of Sheffield believe they have found a cost-effective and energy-efficient way to harvest algae for biofuels. Algae produce an oil which can be taken, processed and turned into biofuel. Algae can be used to for making a wide array of products like vegetable oil, biodiesel, bioethanol and biofuels. Up until now though, harvesting and removing water from the algae has been difficult and costly.
Professor Will Zimmerman and a team of scientists from the U.K. university have come up with a way to make microbubbles that float algae particles to the surface of the water for easy harvest. Microbubbles are currently used by water purification companies as a way to “float out” impurities. But according to the scientists, this is the first time the they have been used on algae. One of the reasons is because doing so can be expensive.
That’s where Zimmerman’s team comes in. They have created a “Sheffield microbubble system” that is said to use far less energy to produce microbubbles—as little as 0.1 percent as much energy. “We thought we had solved the major barrier to biofuel companies processing algae to use as fuel when we used microbubbles to grow the algae more densely,” Professor Zimmerman said in a statement. “It turned out, however, that algae biofuels still couldn’t be produced economically, because of the difficulty in harvesting and dewatering the algae. We had to develop a solution to this problem and once again, microbubbles provided a solution.”
The team’s next challenge will be replicate their system in a pilot plant on a larger, industrial scale. The university is working with Tata Steel to test the the larger-scale system. With algae said to grow 20 to 30 times faster than traditional food crops grown for biofuel production, only time will tell if it will could soon become the dominate way in which biofuels are used. To learn more about Professor Zimmerman’s microbubble research, you can check out his published work, “Microflotation Performance for Algal Separation,” in the Jan. 26 issue of Biotechnology and Bioengineering.