Summary: | The present investigation concerns the potentiality of <i>Rhodopseudomonas</i> sp. cells to produce clean energy such as molecular hydrogen (H<sub>2</sub>). The abovementioned goal could be reached by improving the capability of purple non-sulfur bacteria to produce H<sub>2</sub> via a photofermentative process through the enzyme nitrogenase. <i>Rhodopseudomonas</i> sp. cells were immobilized in calcium alginate gel beads and cultured in a cylindrical photobioreactor at a working volume of 0.22 L. The semi-continuous process, which lasted for 11 days, was interspersed with the washing of the beads with the aim of increasing the H<sub>2</sub> production rate. The maximum H<sub>2</sub> production rate reached 5.25 ± 0.93 mL/h with a total output of 505 mL. The productivity was 40.9 μL (of H<sub>2</sub>)/mg (of cells)/h or 10.2 mL (of H<sub>2</sub>)/L (of culture)/h with a light conversion efficiency of 1.20%.
|