Abstract
Microalgae appear as a sustainable source of biomass with relevant nutritional qualities. Still,regulatory restrictions currently limit the use of eukaryotic microalgae for human consumption to a short list of species dominated by Chlorella spp. Chlorella biomass contains valuable proteins but also interesting lipids, including polyunsaturated fatty acids (PUFA) v3 and v6. The amount of PUFA and the v6/v3 ratio vary significantly depending on the species and cultivation trophic mode. While the lipid profiles of in-lab produced Chlorella has been widely studied, the variability of lipid content in commercial biomasses is barely described. Here, lipid classes and fatty acid profiles of six commercial biomasses of Chlorella spp. as well as those of lab-produced C. sorokiniana grown in photo-autotrophy and in four mixotrophy conditions were characterized. Results showed significant lipid composition variations between the biomasses, such as the triacylglycerols/glycolipids and v6/v3 contents. The v6/v3 ratios were lower inphoto-autotrophic mode (2.5) while they ranged between 1.3 and 8.9 in commercial biomasses. The freefatty acids level was also variable (1.4% to 17.9% of total lipids). As a consequence, Chlorella lipidcontent and quality differed significantly, impacting the potential nutritional benefits of the consumptionof commercial biomass. Processing and post-processing conditions should therefore be carefullycontrolled to optimize lipid profiles