Date

2022-8

Author

Tarlan, Etkin

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Hydrogen (H2) energy has an important place in terms of both reducing environmental pollution problems and having the highest energy content compared to fossil fuels. There are many ways to produce H2, and photofermentation, which is one of the subheadings of biological H2 production, was used in this thesis. Two different strains of Rhodobacter capsulatus strains of photosynthetic bacteria were used: R. capsulatus wild (WT) and uptake hydrogenase deficient mutant YO3 (hup-). In addition to the H2 production, R.capsulatus can synthesize some valuable byproducts such as poly-β-hydroxy butyric acid (PHB). PHB stands out due to its economic value and biodegradable polymer structure. The main objective of this study was to compare of WT and YO3 (hup-) strains of R.capsulatus in terms of H2 and PHB synthesis efficiency. Since PHB accumulates under excess carbon source and stress conditions, 65 mM acetate and 2 mM glutamate were used as carbon and nitrogen sources, respectively. In total, 6 experiments were designed and operated with respect to PHB analysis methods, reactor design and gas collection systems. Anaerobic photobioreactors with 50-350 mL capacity were operated in batch and fed-batch modes. The results revealed that the relationship between H2 and PHB production was directly proportional for the WT strain under the availability of acetate concentration (higher than 20 mM acetate concentration for this study). For YO3 strain, there was generally a reverse relationship between H2 and PHB production.

Subject Keywords

Hydrogen, Photofermentation, Poly-β-hydroxybutyrate (PHB), Rhodobacter capsulatus, Acetate

URI

https://hdl.handle.net/11511/99529

Collections

Graduate School of Natural and Applied Sciences, Thesis