Uncertainties in supply and price of non-renewable energy sources, and the environmental concerns of adverse effects of fossil fuels have led researchers to further explore the realm of alternative fuel sources.
Recent microalgae research at Oklahoma State University’s Robert M. Kerr Food & Agricultural Products Center has done just that.
“Currently, biofuels such as bioethanol and biodiesel are mainly produced from corn and vegetable oils in the U.S.,” said Nurhan Dunford, FAPC oil/oilseed specialist and OSU department of biosystems and agricultural engineering professor. “Today, there is no bioethanol production facility in Oklahoma because the amount of corn grown in the state cannot meet the needs of a bioethanol production facility. At this point, these operations have to rely mostly on feedstock coming from outside the state.”
With the local alternative feedstock need in mind, Dunford and her group of student and faculty researchers have been examining non-food crops such as microalgae as potential biofuel and bioproduct feedstocks.
“Microalgae are microscopic organisms found in both marine and freshwater environments,” Dunford said. “Various types of algae are among the most efficient plants to convert solar energy to chemical energy, and microalgae can accumulate a wide range of commercially important products like oil, sugar, protein, cellulose and high value functional bioactive compounds.”
Microalgae, the non-food feedstock, offer diverse uses. “With microalgae, we can clean waste water while generating biomass,” Dunford said. “Microalgae are capable of absorbing excess plant nutrients from waste water and use CO2 for producing oil, biomass and even useful high value compounds.”
As an alternative to land planted crops, microalgae can grow and thrive in water sources such as ponds or animal waste streams.
“Microalgae systems use far less water than traditional oilseed crops,” Dunford said. “By use of microalgae, it would take only 1 to 3 percent of the existing U.S. crop area to replace half of the petroleum based transportation fuel with biodiesel. More importantly, microalgae do not compete with cropland.”
Research shows many microalgae strains can accumulate as much or more oil than oilseeds.
“Microalgae may have 30 to 70 percent oil, based on dry algal biomass, while soybeans contain about 20 percent oil,” Dunford said. “The high oil content and rapid biomass production make microalgae a very attractive renewable source for bioproduct manufacturing.”
The scope of the research project includes developing a semi-continuous microalgae system that maximizes production of algal biomass with high oil content, captures carbon dioxide produced by power plants and ethanol production facilities, and reduces the adverse impact of agricultural waste water on environment.
“Successful completion of this project will take researchers a step closer to a non-food feedstock source that can be produced on non-agricultural land with less space requirement than today’s feedstocks used for biofuel production,” Dunford said.
Initially, research stemmed from purchasing six microalgae strains from a culture bank.
“Three of the strains are native to Oklahoma, while the other three have high oil content and possess traits of adaptability to the Oklahoma environment and are an interest to many start-up companies,” Dunford said.
Testing began in 10-milliliter test tubes and has advanced to 10-liter bioreactors.
“From 10-milliliter to 1-liter to 5-liter and now to 10-liter bioreactors, testing has been successful in the lab in a controlled environment,” Dunford said. “Today, we can effectively grow and harvest these microalgae strains.”
A graduate student working on the project has had additional success in biomass and oil characterization.
“My graduate student, Yan Zhu, has determined the biomass growth rates and the oil content in biomass generated by these strains,” Dunford said. “Oil characterization and optimization of the process parameters for three different biomass flocculation techniques are in progress.”
From the lab to the OSU Swine Farm
Procedures from the microalgae laboratory testing were mirrored in a study that involved growing microalgae in waste water obtained from a lagoon at OSU’s Swine Farm.
Flint Holbrook, a biosystems and agricultural engineering junior, commenced work on the microalgae project three years ago as a freshman. Holbrook focused on inhabitation of microalgae in animal waste streams.
“My first work on the project was using a computer to grow algae to counteract the labor intensive process,” Holbrook said. “Secondly, I looked at nutrient absorption from animal waste, specifically hog lagoons.”
Holbrook and his team followed the lab-tested protocols to perform the animal waste water experiments.
“We found that the microalgae grew in the wastewater and absorbed nutrients floating in the lagoon,” Holbrook said. “In theory, microalgae could remove pollution, and absorb CO2 and other greenhouse gases.”
According to Dunford, Holbrook’s research demonstrated that one of the Oklahoma native microalgae strains can grow in swine lagoon water with no additional nutrients and removes a significant portion of the excess nitrogen present in the waste water.
“We worked to find the market and determine if we are able to grow microalgae,” Holbrook said. “How do you make it profitable? How do you get out of it more than you put in? In theory, the goal is to help commercialize microalgae and introduce these practices into the market.”
Holbrook’s study received scholarship recognition and funding for continuous work.
Educational outreach and recruitment
Research findings have trickled into other aspects of educational outreach and recruitment.
“One of my goals is to use this research for outreach services,” Dunford said. “The knowledge gained from this project will be incorporated into extension workshops and publications.”
In addition, collaborative efforts of the FAPC and OSU’s biosystems and agricultural engineering department act as student recruiting opportunities.
Dunford said the educational component of this project targets recruitment of undergraduate and graduate students, and the incorporation of the knowledge gained from the project to classroom teaching and hands-on laboratory experiments for students.
Next phases of the project include establishing protocols and mimicking real-life growing conditions.
“Recent research funding from the Department of Transportation through the South Central Sun Grant program will be used to design and install larger microalgae bioreactors in OSU’s biosystems and agricultural engineering greenhouse,” Dunford said.
The long-term goal is to put microalgae strains in an outdoor pond or directly integrate into animal waste water ponds.
“From the liter tests, we can develop processes to recover high value compounds from algal biomass,” Dunford said. “The next step would be the evaluation of economic viability of a commercial scale microalgae growth and processing facility and conversion of algal oil and biomass to biofuels and other high value products. “
Dunford’s research team plans to continue to explore the local biofuel feedstock candidates and other value-added products.
“Our ultimate goal is that results of this on-going study could lead to establishment of an algal biomass-based industry that could produce biofuels and high value-added products in Oklahoma,” Dunford said.
Source: Kylee Willard, FAPC Communications Services Graduate Assistant