Alterations of the lipid content and fatty acid profile of Chlorella protothecoides under different light intensities

•High light intensity improves growth and the total lipid content of Chlorella protothecoides.•The intensity of light affects the fatty acid composition.•An increase in light intensity leads to an increase in MUFA and a decrease in PUFA.•The content of C16–C18 fatty acids increased with the light intensity increase.•The content of 18:3 acid decreased with the light intensity increase. Chlorella protothecoides is a valuable source of lipids that may be used for biodiesel production. The present work shows analysis of the potential of photoheterotrophic cultivation of C. protothecoides under various light intensities aiming to identify the conditions with maximal biomass and lipid content. An increase in light intensity was associated with an increased specific growth rate and a shortened doubling time. Also, the relative total lipid content increased from 24.8% to 37.5% with increase of light intensity. The composition of fatty acid methyl esters was affected by light intensity with the C16–18 fatty acids increased from 76.97% to 90.24% of total fatty acids. However, the content of linolenic acids decreased with the increase of the culture irradiance. These studies indicate that cultures irradiated with high light intensities achieve the minimal specifications for biodiesel quality on linolenic acids and thus are suitable for biodiesel production.