A hardy algae species is showing promise in being able to cut down power plant pollution and making biofuel.
The algae, known as Heterosigma akashiwo, grows rapidly on a gas mixture that has the same carbon dioxide and nitric oxide content as emissions released from a power plant.
“The algae thrive on the gas,” said Kathryn Coyne, associate professor of marine biosciences in the University of Delaware’s College of Earth, Ocean, and Environment. “They grow twice as fast and the cells are much larger in size compared to when growing without gas treatment.”
The algae also make large amounts of carbohydrates, which can convert into bioethanol to fuel vehicles. The findings could have industrial applications as a cost-effective way to cut greenhouse gas pollution when paired with biofuel production.
Heterosigma akashiwo is everywhere throughout the world in the natural environment. Coyne, an expert in algal blooms, discovered the species may have a special ability to neutralize nitric oxide — a harmful gas that poses threats to environmental and human health.
That characteristic prompted Coyne and her team to investigate whether the algae could grow on carbon dioxide without it dying from the high nitric oxide content in power plants’ flue gas, which stopped other attempts by scientists using different types of algae.
A yearlong laboratory experiment shows Heterosigma akashiwo not only tolerates flue gas, but flourishes in its presence. The algae also do not need any additional nitrogen sources beyond nitric oxide to grow, which could reduce costs for raising algae for biofuel production.
“This alone could save up to 45 percent of the required energy input to grow algae for biofuels,” Coyne said.
So far, Coyne found a large increase in carbohydrates when they grew the algae on flue gas compared to air. They also see correlations between the levels of light given to the algae and the quantity of carbohydrates and lipids present in the organisms.
The researchers are exploring opportunities for partnerships with companies to scale up the growth process and more closely examine Heterosigma akashiwo as a biofuel producer.
“Our approach to the issue is to not just produce biofuels, but to also use this species for bioremediation of industrial flue gas to reduce harmful effects even further,” Coyne said.