Selecting the Best Microalgae for Biodiesel Production

Researchers have developed a methodology to analyze the properties of different algal species to select the best microalgae for use as an energy source by taking into account biological, economic, and environmental aspects. Their research findings appear in Journal of Renewable and Sustainable Energy, Dec. 1, 2020 (DOI: 10.1063/5.0010668) by AIP Publishing. The article, “A practical tool for selecting microalgal species for biodiesel production,” is authored by L.A. Martín, C.A. Popovich, M.C. Damiani, and P.I. Leonardi.

Despite the advantages of microalgae and the improvements in culture procedures, relatively few species have been studied as biodiesel feedstock. Different properties have been evaluated for the purpose of selecting suitable microalgal species for biodiesel, including growth rate and lipid content, lipid productivity, fatty acid composition, and biodiesel quality. Standard methods for determining these properties, however, are often hampered by the volume of material required for analysis and the need for specific equipment, resulting in high costs.

“Our work makes it possible to perform an analysis of the microalgae based on laboratory-scale data, without the need to go through a pilot-scale experiment,” said author Lucas Martín, of the National Scientific and Technical Research Council.

The researchers created an overall score that standardized criteria for potential large-scale cultures, covering biomass and oil production requirements, triacylglyceride content and biodiesel quality. They examined nine types of microalgae and found the native benthic diatoms H. coffeaeformis, Navicula cincta, and N. gregaria appeared to be the most promising species for biodiesel production.

Schematic diagram for the process to obtain overall score for evaluating microalgal species for biodiesel production. Credit: Lucas Martín

“This tool provides a useful criterion for selecting suitable microalgal species for commercial biodiesel production,” said Dr. Martín. “The most surprising thing was the low score obtained by species that are widely studied for the production of biodiesel such as Chlorella vulgaris.”

The researchers also uncovered promising new areas for further research. They found many diatom species have favorable characteristics for sustainable biofuel production and are robustly resistant to extreme environmental conditions. This species, however, has not yet generated a significant degree of scientific interest in the bioenergy field but should be at the forefront of bioprospecting efforts for biodiesel production say the researchers.

“We think this procedure could be applied to any other bioproducts that are being produced for microalgae, in addition to biodiesel,” said Dr. Martín.