Potential of Outdoor Cultivation of Macroalgae for Biodiesel Production

A team of Chinese researchers reported in the journal Bioresource Technology the results of a study that evaluated the feasibility of producing biodiesel from macroalgae under outdoor conditions using urea as nutrient source.

Oil-producing macroalgae have been considered as a promising feedstock for biodiesel production because of their photosynthetic efficiency, high lipid content, and ability to grow in extreme environments. Most experiments on biodiesel production from algae were conducted in the laboratory, with fluorescent lamp as light source. In the present study, Chinese researchers demonstrated the outdoor cultivation of Chlorella sp. (FACHB-1748) under natural sunlight. The macroalgae was isolated from a pond in Huang Gang, China. As nitrogen is required for algal nutrition, the researchers used urea, a low cost and readily available source of nitrogen, to grow the macroalgae under an optimized rate of application.

The researchers found highest algal biomass and lipid productivity with 0.1 g/L urea in large photobioreactors under such outdoor conditions. They also found a significant improvement in lipid content and overall lipid yield with the addition of sodium chloride and acetate. The quality and properties of the biodiesel produced under these conditions were reported to have satisfied the criteria of some international fuel standards based on certain parameters.