Hydrogen production by hup(-) mutant and wild-type strains of Rhodobacter capsulatus from dark fermentation effluent of sugar beet thick juice in batch and continuous photobioreactors

Uyar, Basar
Gurgan, Muazzez
Ozgur, Ebru
Gündüz, Ufuk
Yücel, Ayşe Meral
Eroglu, Inci
Photofermentative production of hydrogen is a promising and sustainable process; however, it should be coupled to dark fermentation to become cost effective. In order to integrate dark fermentation and photofermentation, the suitability of dark fermenter effluents for the photofermentative hydrogen production must be demonstrated. In this study, thermophilic dark fermenter effluent (DFE) of sugar beet thick juice was used as a substrate in photofermentation process to compare wild-type and uptake hydrogenase-deficient (hup (-)) mutant strains of Rhodobacter capsulatus by means of hydrogen production and biomass growth. The tests were conducted in small-scale (50 mL) batch and large-scale (4 L) continuous photobioreactors in indoor conditions under continuous illumination. In small scale batch conditions, maximum cell concentrations were 0.92 gdcw/L (c) and 1.50 gdcw/L (c), hydrogen yields were 34 % and 31 %, hydrogen productivities were 0.49 mmol/(L (c)center dot h) and 0.26 mmol/(L-c center dot h), for hup (-) and wild-type cells, respectively. In large-scale continuous conditions, maximum cell concentrations were 1.44 gdcw/L (c) and 1.87 gdcw/L (c), hydrogen yields were 48 and 46 %, and hydrogen productivities were 1.01 mmol/(L (c)center dot h) and 1.05 mmol/(L (c)center dot h), for hup (-) and wild-type cells, respectively. Our results showed that Rhodobacter capsulatus hup (-) cells reached to a lower maximum cell concentration but their hydrogen yield and productivity were in the same range or superior compared to the wild-type cells in both batch and continuous operating modes. The maximum biomass concentration, yield and productivity of hydrogen were higher in continuous mode compared to the batch mode with both bacterial strains.


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Ozgur, Ebru; Mars, Astrid E.; Peksel, Beguem; Louwerse, Annemarie; Yucel, Meral; Gündüz, Ufuk; Claassen, Pieternel A. M.; Eroglu, Inci (2010-01-01)
Biological hydrogen production using renewable resources is a promising possibility to generate hydrogen in a sustainable way. In this study, a sequential dark and photofermentation has been employed for biohydrogen production using sugar beet molasses as a feedstock. An extreme thermophile Caldicellulosiruptor saccharolyticus was used for the dark fermentation, and several photosynthetic bacteria (Rhodobacter capsulatus wild type, R. capsulatus hup(-) mutant, and Rhodopseudomonas palustris) were used for t...
Photofermentative hydrogen production from molasses in tubular photobioreactor with pH control
Oflaz, Fatma Betül; Koku, Harun; Department of Chemical Engineering (2019)
Biological hydrogen production has the potential to supply hydrogen from various wastes as feedstock and operation under ambient conditions. In order to obtain cost effective production, photobioreactors (PBRs) that can operate for long durations while utilizing waste are necessary. Two primary issues limiting the duration are decrease in pH and the non-optimal C/N ratio. The main aim of this study was to construct and operate a pH control system for a pilot scale photobioreactor (20 L) to achieve prolonged...
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...
Photofermentative hydrogen production from molasses: Scale-up and outdoor operation at low carbon-to-nitrogen ratio
Savasturk, Dilan; Kayahan, Emine; Koku, Harun (2018-06-28)
Photofermentative hydrogen production was carried out under outdoor conditions with a Rhodobacter capsulatus strain on molasses, a renewable and sustainable feedstock. An existing photobioreactor design was scaled-up from 9 L to 20 L. The decreased carbon-to nitrogen (C/N) ratio of 13.0, compared to our previous work, accelerated growth and resulted in a reduced lag period for hydrogen production as well as higher productivities in the exponential phase. However, the low C/N ratio also promoted a high optic...
Potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by Rhodobacter capsulatus
Ozgur, Ebru; Afsar, Nilufer; de Vrije, Truus; Yucel, Meral; Gündüz, Ufuk; Claassen, Pieternel A. M.; Eroglu, Inci (2010-01-01)
Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch ...
Citation Formats
B. Uyar, M. Gurgan, E. Ozgur, U. Gündüz, A. M. Yücel, and I. Eroglu, “Hydrogen production by hup(-) mutant and wild-type strains of Rhodobacter capsulatus from dark fermentation effluent of sugar beet thick juice in batch and continuous photobioreactors,” BIOPROCESS AND BIOSYSTEMS ENGINEERING, pp. 1935–1942, 2015, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/31629.