Separating photosinthetic hydrogen production from photosynthetic oxygen production
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The goal of this thesis is to develop concepts to separate photosynthetic hydrogen production from oxygen production. For this the strains will be generate and with deficient in the photosystems (PSI and PSII) that mediate oxygen production and hydrogen production, respectively. The potential to interfacing these two strains via artificial and natural electron transport systems will be evaluated. The growth experiment will be estimated for mutants on different iron and manganese sources, with light or dark condition. Cyanobacteria are large and diverse group of prokaryote. It is composed of two main membrane, cell wall and cytoplasmic membrane. Within the membrane the photosynthetic apparatus is incorporated where photosynthesis take place. Photosynthesis is the most important process on Earth, by which the oxygen gas is produced and released. The photosynthesis began with light been absorbed by the pigment on the surface of the photosystem II. Energy from the absorbed electron then is used for water oxidation. The electron from water molecule together with electron from the light are transferred to cytochrome b6f complex. Cytochrome b6f complex catalyzes the transfer of electrons from plastoquinol to plastocyanin. It mediates the electrons from photosystem II complex to photosystem I complex. The electron is re-energies and then used to drive synthesis ATP. The Synechocystis sp. PCC6803 was used to create mutants with deficient photosystems (PSI and PSII). The mutant with deficient in PSI was created by deletion slr1834-1835 gene, that is responsible for production P700 apoprotein subunit Ia and Ib. The PSII deficient were create by deletion slr0906 gene, which produce core light harvesting protein. The growth experiments were performed with different iron and manganese sources and exposed to the dark condition and light condition. The results showed that all mutants possess ability to growth on all the media that was made for this experiment. However, there are small differences in growth rate on different media. The Δslr1834-1835 showed increased growth on media that were supplemented with manganese sources exposed to dark condition, compared to the Δslr0906 mutant. The Δslr0906 showed increased growth rate on media supplemented with iron and manganese sources exposed to dark condition. The strains grown on media exposed to light condition showed increased growth rate compared to the growth under the darkness. The strains that were grown under the light condition showed the most increased growth rate over the time. The interfacing two strains via artificial and natural electron transport systems will not be evaluated. This is due to lack of time.