Chemical Characterization of Microcystis aeruginosa for Feed and Energy Uses

Cyanobacterial blooms and strains absorb carbon dioxide, drawing attention to its use as feed for animals and renewable energy sources. However, cyanobacteria can produce toxins and have a low heating value. Herein, we studied a cyanobacterial strain harvested during a bloom event and analyzed it to use as animal feed and a source of energy supply. The thermal properties and the contents of total nitrogen, protein, carbohydrate, fatty acids, lipid, and the presence of cyanotoxins were investigated in the Microcystis aeruginosa LTPNA 01 strain and in a bloom material. Microcystins (hepatotoxins) were not detected in this strain nor in the bloom material by liquid chromatography coupled to mass spectrometry. Thermogravimetric analysis showed that degradation reactions (devolatilization) initiated at around 180 °C, dropping from approximately 90% to 20% of the samples’ mass. Our work showed that despite presenting a low heating value, both biomass and non-toxic M. aeruginosa LTPNA 01 could be used as energy sources either by burning or producing biofuels. Both can be considered a protein and carbohydrate source similar to some microalgae species as well as biomass fuel. It could also be used as additive for animal feed; however, its safety and potential adverse health effects should be further investigated.