Lipid profile analysis of three new Amazonian cyanobacteria as potential sources of biodiesel

•Microbial lipids as possible fossil fuel substitutes.•Lipid profiles of Amazon Cyanobium sp., Limnothrix sp. and Nostoc sp.•Limnothrix sp. had a better lipid profile and produced high amounts of C16:0.•Limnothrix sp. had better biodiesel quality parameter values. The demand for microbial lipids as possible fossil fuel substitutes has prompted worldwide synthetic biofuel research. The present study surveyed the lipid profiles of three Amazonian cyanobacterial strains, Cyanobium sp., Limnothrix sp. and Nostoc sp. cultivated in two culture media, ASM-1 and BG-11, to evaluate their fatty acid composition and to measure biodiesel quality parameters. All strains showed good growth in the two culture media, but the Limnothrix sp. had a better lipid profile and produced high amounts of C16: 0, which is favorable for the production of biodiesel. This strain also had better biodiesel quality parameter values showing high oxidative stability (34.90 h) and a cetane number (58.06) above the minimum established by the ASTM (American Society for Tests and Materials); these values were measured by the program Biodiesel Analyzer © Ver. 2.2.