| Insights into light-dependent hydrogen production and fermentation in Chlamydomonas reinhardtii by analyses of gene regulation |
| C. Lambertz, J. Jacobs, A. Hemschemeier and T. Happe |
| Ruhr-University of Bochum, Biochemistry of plants, Photobiotechnology, Universitätsstraße 150, 44780 Bochum, Germany |
| Chlamydomonas reinhardtii has a complex anaerobic metabolism that is marked by the production of hydrogen gas, formate and ethanol [1, 2], catalysed by an [FeFe]-hydrogenase coupled to photosynthesis by the natural electron donor ferredoxin [3, 4] and by the bacterial-like pyruvate formate lyase (PFL1) [5], respectively. A sustained anaerobic metabolism which has attracted public interest because of the production of relatively large amounts of hydrogen is established when C. reinhardtii cells are deprived of sulphur [6]. Under this condition, the algae down-regulate photosynthesis and anaerobize themselves by respiratory oxygen uptake. It was shown recently that the transcription of a gene encoding a novel ferredoxin, FdxA, increases strongly upon S-deprivation and artificial anaerobiosis, while the transcription of the gene encoding the photosynthetic ferredoxin, PetF, decreases. This upregulation of the fdxA-gene indicates an essential role of FdxA in the anaerobic metabolism of C. reinhardtii. We have analyzed the regulation of the fdxA-gene in response to O2 deprivation by reporter gene assays. The final objective is to compare the regulation of several anaerobically induced genes that are involved in light-dependent H2-production and photofermentation in C. reinhardtii to get a deeper understanding of participating signal transduction and metabolic pathways.
References: |
| e-mail address of presenting author: Camilla.Lambertz@rub.de |