Effect of inoculum concentration, pH, light intensity and lighting regime on hydrogen production by phototrophic microbial consortium

Photobiological hydrogen production using a bacterial consortium has advantages over pure cultures regarding application to wastewater treatment. Photo-H2 production from organic acids, which were produced by dark fermentation, must be studied in detail to make a hydrogen production process in two stages efficient. In this scenario, our study aimed to determine the optimized culture conditions for hydrogen production by a phototrophic bacterial consortium. The inoculum concentration, pH, light intensity and illumination protocols were the parameters that we evaluated. The optimal conditions for hydrogen production were inoculum concentration of 0.2 g VSS L−1, pH 7.0, light intensity of 5 klux, with a constant illumination regime. The highest hydrogen production potential (P) and substrate conversion efficiency (SCE) were 41.5 mmol H2 L−1 culture and 25.4%, respectively, with a COD removal of 95%.