Hydrogen production properties of Rhodobacter capsulatus with genetically modified redox balancing pathways

Ozturk, Yavuz
Gokce, Abdulmecit
Peksel, Begum
Gurgan, Muazzez
Ozgur, Ebru
Gündüz, Ufuk
Eroglu, Inci
Yucel, Meral
Rhodobacter capsulatus produces molecular hydrogen under the photoheterotrophic growth condition with reduced carbon sources (organic acids). Under this condition, ubiquinol pool is over reduced and excess reducing equivalents are primarily consumed via the reduction of CO2 through the Calvin-Benson-Bassham (CBS) pathway, the dimethylsulfoxide reductase (DMSOR) system or by the reduction of protons into hydrogen gas with the use of nitrogenase to maintain a balanced intracellular oxidation-reduction potential (redox balance). In order to investigate the effect of redox balancing pathways on nitrogenase-dependent hydrogen production, CO2 fixation was blocked by inactivating the phosphoribulokinase (PRK) of CBS pathway in wild type (MT1131), uptake-hydrogenase deficient strain (YO3), and cyt cbb(3) oxidase and uptake-hydrogenase deficient double mutant (YO4) strains. The hydrogen production properties of newly generated strains deficient in the CBB pathway were analyzed and compared with wild type strains. The obtained data indicated that, the total hydrogen production was increased slightly in CBB deficient mutant of YO3 and YO4 (4.7% and 12.5% respectively). Moreover, the maximum hydrogen production rate was increased by 13.3% and 12.7% for CBB deficient mutant of MT1131 and YO3 respectively. It was also observed that under the photoheterotrophic growth condition with ammonium as a nitrogen source, PRK deficient strains gave photoheterotrophically competent ammonium insensitive revertants. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Hydrogen production by using Rhodobacter capsulatus mutants with genetically modified electron transfer chains
Ozturk, Yavuz; Yucel, Meral; Daldal, Fevzi; Mandaci, Sevnur; Gündüz, Ufuk; Turker, Lemi; Eroglu, Inci (2006-09-01)
In Rhodobacter capsulatus excess reducing equivalents generated by organic acid oxidation is consumed to reduce protons into hydrogen by the activity of nitrogenase. Nitrogenase serves as a redox-balancing tool and is activated by the RegB/RegA global regulatory system during photosynthetic growth. The terminal cytochrome cbb3 oxidase and the redox state of the cyclic photosynthetic electron transfer chain serve redox signaling to the RegB/RegA regulatory systems in Rhodobacter. In this study, hydrogen prod...
Kinetic analysis of photosynthetic growth, hydrogen production and dual substrate utilization by Rhodobacter capsulatus
Sevinc, Pelin; Gündüz, Ufuk; EROĞLU, İNCİ; Yucel, Meral (2012-11-01)
Rhodobacter capsulatus is purple non-sulfur (PNS) bacterium which can produce hydrogen and CO2 by utilizing volatile organic acids in presence of light under anaerobic conditions. Photofermentation by PNS bacteria is strongly affected by temperature and light intensity. In the present study we present the kinetic analysis of growth, hydrogen production, and dual consumption of acetic acid and lactic acid at different temperatures (20, 30 and 38 degrees C) and light intensities (1500, 2000, 3000, 4000 and 50...
Hydrogen production by Rhodobacter sphaeroides OU001 in a flat plate solar bioreactor
Eroglu, Inci; Tabanoglu, Altan; Gündüz, Ufuk; Eroglu, Ela; Yucel, Meral (2008-01-01)
Rhodobacter sphaeroides O.U.001 can produce hydrogen under anaerobic conditions and illumination. The objective of this study was to investigate the performance of an 81 flat plate solar bioreactor operating in outdoor conditions. Different organic acids were used as carbon sources (malate, lactate and acetate) and olive mill waste water was used as a sole substrate source. The consumption and the production of the organic acids were determined by HPLC. The accumulation of by-products, such as poly-beta-hyd...
Hydrogen production by different strains of Rhodobacter sphaeroides
Gündüz, Ufuk; Yucel, M; Turker, L; Eroglu, L (2000-06-15)
Utilisation of solar energy by photosynthetic microorganisms for H-2 production attracts much interest due to unlimited supply of energy. It is important to identify the most effective strain in terms of hydrogen production for the feasibility of the process. Four different strains of Rhodobacter sp. were grown in a water-jacketed cylindrical glass-column photobioreactor under anaerobic conditions. Growth characteristics and hydrogen production rates were determined. Comparison between strains of Rhodobacte...
Hydrogen gas production by combined systems of Rhodobacter sphaeroides OU001 and Halobacterium salinarum in a photobioreactor
Zabut, Baker; EI-Kahlout, Kamal; Yucel, Meral; Gündüz, Ufuk; Turker, Lemi; Eroglu, Inci (2006-09-01)
Rhodobacter sphaeroides O.U.001 is a photosynthetic non-sulfur bacterium which produces hydrogen from organic compounds under anaerobic conditions. Halobacterium salinarum is an archaeon and lives under extremely halophilic conditions (4 M NaCl). H. salinarum contains a retinal protein bacteriorhodopsin in its purple membrane which acts as a light-driven proton pump. In this study the Rhodobacter sphaeroides O.U.001 culture was combined with different amounts of packed cells of H. salinarum S9 or isolated p...
Citation Formats
Y. Ozturk et al., “Hydrogen production properties of Rhodobacter capsulatus with genetically modified redox balancing pathways,” INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, pp. 2014–2020, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31117.