Metabolic and gene expression changes triggered by nitrogen deprivation in the photoautotrophically grown microalgae Chlamydomonas reinhardtii and Coccomyxa sp. C-169

► N deprivation induces starch and triacylglycerol accumulation in green microalgae. ► Chlorophyll and protein contents are considerably reduced. ► Protein turnover may provide carbon intermediates/energy for TAG synthesis. ► N depletion also affects the expression of lipid biosynthesis genes. ► Anabolic and catabolic processes underlie microalgal production of biofuel precursors.