Green energy from microalgae
A number of questions must be answered before the use of microalgae as
biofuel feedstock becomes commercially feasible. "Scientists are looking
to nature for solutions to the global energy crisis, and I'm convinced
that breakthrough results will be achieved in the next 5 - 10 years,"
The production of biodiesel from microalgae instead of controversial palm oil has stirred immense interest within the scientific community worldwide. For example, the U.S. federal government has made significant investments in algae research.
"Research on microalgae has spawned numerous spin-off companies in the USA. Some of the companies have already signed contracts to supply microalgal biodiesel to the U.S. Navy. This suggests that the commercial breakthrough of algae-based diesel is imminent," says Postdoctoral Researcher Aino-Maija Lakaniemi from the Department of Chemistry and Bioengineering at Tampere University of Technology (TUT).
Microalgae more versatile than previously assumed
Last spring, Lakaniemi completed her doctoral dissertation that explored microalgal cultivation and utilization in energy production. Her results demonstrated that microalgae are a more versatile source of biofuels than they have been given credit for. Hydrogen, methane, bioelectricity and butanol were derived from algae during the research project at TUT.
"Microalgae are diverse sources of energy. For example, when we produced electricity from algal biomass in microbial fuel cells, butanol was generated as a by-product."
The lipid content of selected species of microalgae was also analysed. Strains with high lipid content are best suited for making biodiesel.
"The cultivation conditions are important too, because the lipid content can be controlled by regulating the amount of nitrogen and CO2 in the algal culture," adds Lakaniemi.
WHO: Aino-Maija Lakaniemi
- 29-year-old postdoctoral researcher at the Department of Chemistry and Bioengineering of TUT.
- Completed a master's degree at TUT in 2007 and a doctorate in 2012.
- "I've found my calling. The idealist in me wants to save the world."
- Is currently involved in the BioelectroMET project that aims to generate energy using microbial fuel cells and recover metals from mining waters.
Help from bacteria
Lakaniemi compared two species of microalgae, the freshwater microalga Chlorella vulgaris and marine microalga Dunaliella tertiolecta. They were cultivated in different types of photobioreactors, such as transparent, 20-litre bags with a built-in CO2 inlet valve. Lamps mimicking sunlight were placed near the bags.
"Often the growth medium and photobioreactors are sterilized to eliminate the growth of bacteria, because algae and bacteria compete for the same nutrients. Since sterilization is very expensive, we studied which bacteria were present in the algal cultures. We're aiming to find out later on whether some bacteria could even promote algal growth."
The results of the comparison confirmed that different algal strains harbour different types of bacteria. Previous research has indicated that some bacteria may even promote the growth of algae, for example, by consuming excess oxygen present in the cultivation environment.
Wastewater turned into energy?
The mass-production of microalgae is still expensive and challenging, even though there are large-scale algae plantations in Asia, where algae are used as nutritional supplements.
"Algal production in outdoor ponds is possible in Finland only in the summer months, but cultivation in wastewater may be a viable alternative throughout the year."
"To grow, algae need large amounts of phosphorus and nitrogen, which are the two main culprits behind the eutrophication in our lakes and rivers. We should find a species of algae that thrives in polluted water and low temperatures. What could be better than cheap fuel and cleaner waters?"
Aino-Maija Lakaniemi became interested in microalgae about five years ago.
"Visiting FiDiPro Professor Olli Tuovinen from Ohio State University in the USA joined our department about the same time when we were conducting a small-scale algal biofuels project. We got together to weigh potential new research avenues and ended up pursuing research on microalgae."
"Microalgae played a central role in the origins of life. According to the theory of evolution, cyanobacteria that are also known as blue-green algae were the first photosynthetic organisms on Earth."