Co-production of bioH2 and biomasses rich in oil from two Rhodopseudomonas Palustris strains: 42OL and 6A

It is well-known that non-sulfur photosynthetic bacteria such as Rhodopseudomonas palustris produces bioH2 through a photo-fermentation process. In this study, a co-production of biofuels (hydrogen and oil), so-called green energies, has been investigated. Two Rhodopseudomonas palustris strains: 42OL and 6A were studied for this production of clean energy. Experiments were carried out indoors under continuous light of differing intensities. Both bacteria strains demonstrated that biomasses rich in oil could be produced during bioH2 photoevolution by using a synthetic medium containing either acetic or malic acids. Both culture broths added consisted of glutamate. At the end of every run, the biomasses were stored and analyzed in order to determine their oil content. The highest cumulative hydrogen (3,162 ml) was attained from Rhodopseudomonas palustris, strain 42OL, when it was grown in the culture broth containing malic acid. The same strain (42OL) also produced biomasses with the highest oil content (41.4 %). In general, in the bacteria grown in the culture broth containing acetic acid, the production of bioH2 decreased and the oil content increased significantly in dry-biomass. The other bacteria strain (6A) showed a reduced capability for both productions of green energy. It was demonstrated that the low capability to produce both bioH2 and oil from the Rhodopseudomonas palustris, strain 6A, was due to the specific growth rate of the strain 6A, which was lower than that of the 42OL.