CFD modeling of hydrodynamics and optimization of photofermentative hydrogen production by Rhodopseudomonas palustris DSM 123 in annular photobioreactor

• CFD modeling of hydrodynamics in triple jacketed photobioreactor with uniform light distribution.
• Variations in FeCl3 concentration and C/N ratio of production media for hydrogen production by Rhodopseudomonas palustris strain DSM 123.
• Optimization of the process parameters by 3k full factorial design.
• Mathematical modeling on substrate utilization for biomass and kinetics of substrate consumption for H2 production by PNS bacteria.

H2 has the highest energy density among the other known fuels (143 GJ tonne−1). The present study is focused on spatial aspects of light patterns. Here, Rhodopseudomonas palustris strain DSM 123 was used for biohydrogen production in the triple jacketed photobioreactor (working volume 1 L) with light intensity (15 ± 1.1 W m−2), temperature (33 ± 1) °C, initial pH (6.7 ± 0.1), inoculum volume 10% (v/v), and 250 rpm stirring. Three factor three level full factorial designs was used to optimize the concentration of three critical medium components DL malic acid, L glutamic acid and FeCl3 having high impacts on H2 production. Surface and contour plots of the regression models revealed optimum H2 production rate of 6.885 mL H2 L−1 h−1 showing correlation with experimental optimum H2 production rate of 7.0 mL H2 L−1 h−1. In photobioreactors, turbulent flow conditions and light gradients may occur. CFD simulation study confirmed the advantages of designed annular PBR towards uniform fluid dynamics and heat transfer throughout the reactor. Mathematical modeling on substrate utilization for biomass and kinetics of substrate consumption for H2 production by PNS bacteria gave good simulated results. Modified Gompertz equation yielded good simulated fitting with experimental value for H2 production by Rhodopseudomonas palustris DSM 123.