Using waste gas from power plant flues to produce a green product that can fuel cars and trucks in the future without unwanted emissions may be a story that is hard to swallow.

But that is one of the projects researchers at the Corpus Christi Mariculture Research Laboratory is working on, and they say once their research is complete, the earth should be a better place for it.

It's no secret that research and development for alternative fuel sources—corn, sugarcane, corn stover and other crops—has been in the spotlight as the search for products that can be used to produce biofuel broadens.

But for several years researchers have been looking at algae as a potential alternative, and now, thanks in part to researchers at the Texas AgriLife Mariculture Research Center in Corpus Christi, producing biomass from new varieties of microalgae is painting a positive picture for the prospect of a greener fuel source in the years ahead.

Dr. Carlos Fernandez, a Texas AgriLife plant physiologist, says work in Corpus Christi involves both raceways, large aquatic tanks located near the Intercoastal waterway, and a series of biomass reactors housed in a laboratory at the Texas AgriLife Center near Robstown.

Instead of growing corn on fertile cropland, Fernandez says researchers are using saltwater from a nearby bay and carbon dioxide (CO₂) emissions from an adjacent electrical production plant to enrich microalgae growth in the high saline environment at the Center—a site unsuitable for almost any other use.

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"The work that we do focuses on quantifying the basic responses of microalgae growth to the environment. We have four bioreactors in the Robstown center where we can control environmental conditions such as light, temperatures, pH balance, salinity, nutrients, and CO₂supplements, and we have finished one set of studies where we looked at light and temperatures and their effect on microalgae growth, and we are now entering a new stage of research to address other conditions," Fernandez said.

Nutrition studies

New studies look at different levels of nutrition, he says, because nutrition is a major component of the cost of large scale microalgae production. The idea is to produce microalgae with the right combination of nutrients and environmental variables to make biofuel production cost effective.

"We can control the environment in the bioreactors inside the Robstown lab, but we cannot control the weather outside, so the idea is to develop a model that will allow us to better manage those systems outside of a controlled environment," he added.

In the outdoor systems like the raceways, researchers have been working on various species of algae that will grow better and faster.

"One of the things we are doing is working on a combination of species to get better stability in our production of microalgae. We are hoping to develop models that will allow us to conduct larger scale production models," he said.

According to researchers, the main advantages of microalgae production, particularly in salt water, is to avoid competing with urban areas, agriculture and other industry for use of fresh water. Fernandez says another advantage is that growing microalgae in saltwater raceways on land that is not suitable for other types of agriculture eliminates competition for acres used for food crop production.

Another advantage to producing microalgae as a fuel source is that one day it may be possible to recycle nutrients from wastewater generated at municipal treatment facilities for use in the raceways, further providing environmental benefits. Fernandez says this will help municipal wastewater treatment operations reduce costs and will provide for a greener process because the algae will clean up the wastewater.

If researchers can produce algae that produce high amounts of oil and grow fast, a commercial partner could then grow large amounts of it, extract the oil, convert that oil into gasoline or diesel fuel and sell it just like at a normal gasoline pump. One advantage is that fuels derived from algae would be easier on the environment because they don’t emit any excess carbon into the atmosphere.

"Lastly, we are looking to enrich our biomass cultures utilizing CO₂emissions from facilities like the Barney M. Davis Power Station in Flour Bluff, which is a natural gas powered system that produces CO₂emissions," he said. The Mariculture Research Centeris located adjacent to the power station. "Also other types of industrial plants produce carbon dioxide and our idea is to capture these unwanted emissions and put them to good use in the production of microalgae to further benefit the environment."

Making progress

It may be years before commercial scale raceways can be developed and large volumes of biomass developed into biofuels, however, but Fernandez says researchers are making a lot of progress.

Currently, his research team is getting biomass production on the order of 0.8 grams of dry ash-free biomass per liter of microalgae culture. While that is not sufficient for commercial production, he says in the bioreactors researchers are using, that number nearly doubles, approximately 1.6 grams of dry material of biomass per liter of microalgae production. If production ratios increase much more, we may see large commercial microalgae production facilities within a few years.

While much of the work in the Corpus Christi facilities deals with biofuel research, in addition to producing microalgae, researchers are also focusing on developing super-intensive culture techniques for commercial production of shrimp for human consumption and for live-bait shrimp.

Emphasizing environmental stewardship, the Mariculture Laboratory works to minimize environmental impact through use of zero-exchange, closed recirculating aquaculture systems (RAS), while testing feed formulations, substituting plant-based ingredients in place of fish meal and fish oil.

The Lab focuses on research to promote development of new industries including production of algae biomass for biofuel, and cultivation and management of native halophyte plants to reduce the impact of aquaculture effluents and for production of biofuel.

Fernandez says the AgriLife research team is working in collaboration with a number of other researchers and programs including the U.S. Marine Shrimp Farming Program, Drs. Lacy & Nikolov, Texas A&M University in College Station, researchers at Texas A&M facilities in Galveston and Kingsville, researchers at Auburn University and Ben Gurion University in Israel, among others.

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