Hydrogen production by Rhodopseudomonas palustris WP 3-5 in a serial photobioreactor fed with hydrogen fermentation effluent

► A lab-scale serial photobioreactor was constructed. ► Better hydrogen production rate was obtained when the photobioreactor was operated under cellular recycling at a HRT of 8 h. ► 0.4 x dilution ratio was the suitable influent dilution ratio. ► Column 1 reactor in the serial photobioreactor successfully consumed ammonia for cell synthesis. ► The average hydrogen production rate was 205 mL-H2/L/d.