Effects of nitrogen source heterogeneity on nutrient removal and biodiesel production of mono- and mix-cultured microalgae

•Effects of nitrogen on nutrient removal and biodiesel production of mono- and mix-cultured microalgae was investigated.•Microalgae co-culture could remove 70.4%–74.1% nitrogen.•Algae grown in media with different nitrogen sources had better growth performances.•The ultimate biomass increase and productivity in the mix-culture were the highest.•The biodiesel yields in this study ranged from 8.5–11.2 g-biodiesel/100 g-dry weight.