Effects of light-dark cycles on photosynthetic bacteria wastewater treatment and valuable substances production.

•The first report of effects of light-dark cycles on PSB wastewater treatment.•Varying light-dark cycles achieved higher substances yields at given energy.•24 h light/24 h dark cycle led the best biomass production and NH3-N removal.•3 h light/3h dark cycle led the highest protein and coenzyme Q10 production.