Biophotolysis-based hydrogen and lipid production by oleaginous microalgae using crude glycerol as exogenous carbon source

Abstract

Microalgae are known as potential biofuel producers due to their high theoretical light conversion efficiencies. To develop simultaneous production process of hydrogen and lipids, several oleaginous microalgae were screened for their ability to produce hydrogen using crude glycerol as a low-cost exogenous carbon source. All microalgae could grow on crude glycerol and accumulated high content of lipids (>20%), but only Chlorella sp. produced considerable amount of hydrogen under anaerobic condition. The optimal conditions for hydrogen and lipid production by this microalga were: crude glycerol at glycerol concentration of 16 g/L, initial pH 6.8 and light intensity of 48 μmol photon m−2 s−1. These conditions gave the maximum hydrogen production of 10.31 ± 0.05 mL/L in serum bottle and 11.65 ± 0.65 mL/L in 1 L bioreactor along with lipid content >40% in the recovered microalgal biomass. Exploring biohydrogen production coupled with lipid production by oleaginous microalgae may contribute greatly to the sustainable production of biofuels by microalgae.