Sulfur heterogeneity: A non-negligible factor in manipulating growth and lipid accumulation of Scenedesmus obliquus at a relatively high ratio of carbon to nitrogen

•Algal growth was boosted by various forms of sulfur with different dose dependent.•Effect of nitrogen on carbon assimilation in cells was regulated by sulfur form.•Sulfate was more beneficial to increase lipid productivity than other form.•Sulfur induced changes in expression of genes encoding lipid-related enzymes.