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
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 production of various R. capsulatus strains harboring the genetically modified electron carrier cytochromes or lacking the cyt cbb(3) oxidase or the quinol oxidase were compared with the wild type. The results indicated that hydrogen production of mutant strains with modified electron carrier cytochromes decreased 3- to 4-fold, but the rate of hydrogen production increased significantly in a cbb(3) mutant. Moreover, hydrogen production efficiency of various R. capsulatus strains further increased by inactivation of uptake hydrogenase genes. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.


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 (2012-01-01)
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 potenti...
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...
Hydrogen generation from hydrolysis of sodium borohydride using Ru(0) nanoclusters as catalyst
Özkar, Saim (Elsevier BV, 2005-12-08)
Sodium borohydride is stable in aqueous alkaline solution, however, it hydrolyses in water to hydrogen gas in the presence of suitable catalyst. By this way hydrogen can be generated safely for the fuel cells. Generating H-2 catalytically from NaBH4 solutions has many advantages: NaBH4 solutions are nonflammable, reaction products are environmentally benign, rate of H-2 generation is easily controlled, the reaction product NaBO2 can be recycled, H-2 can be generated even at low temperatures. All of the cata...
Hydrogen generation from the hydrolysis of sodium borohydride by using water dispersible, hydrogenphosphate-stabilized nickel(0) nanoclusters as catalyst
Metin, Oender; Özkar, Saim (Elsevier BV, 2007-08-01)
Water-dispersible nickel(0) nanoclusters are prepared from the reduction of nickel(II) acetylacetonate by sodium borchydride in aqueous solution and stabilized by hydrogerphosphate anion. Hydrogenphosphate-stabilized nickel(0) nanoclusters were characterized by using XPS, FT-IR, UV-Vis and NMR spectroscopic methods. As the first example of water-dispersible nickel(0) nanoclusters, they were employed as catalyst in the hydrolysis of sodium borohydride. Hydrogenphosphate-stabilized nickel(0) nanoclusters were...
Hydrogen generation from the hydrolysis of hydrazine-borane catalyzed by rhodium(0) nanoparticles supported on hydroxyapatite
Celik, Derya; Karahan, Senem; Zahmakiran, Mehmet; Özkar, Saim (2012-03-01)
Herein, we report the preparation and characterization of rhodium(0) nanoparticles supported on hydroxyapatite (Ca-10(OH)(2)(PO4)(6), HAP) and their catalytic use in the hydrolysis of hydrazine-borane, which attracts recent attention as promising hydrogen storage materials. Hydroxyapatite supported rhodium(0) nanoparticles were readily prepared by the hydrazine-borane reduction of rhodium(III)-exchanged hydroxyapatite in situ during the hydrolysis of hydrazine-borane at room temperature. Characterization of...
Citation Formats
Y. Ozturk et al., “Hydrogen production by using Rhodobacter capsulatus mutants with genetically modified electron transfer chains,” INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, pp. 1545–1552, 2006, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/30104.