Biohydrogen production by immobilized purple nonsulfur bacteria

Sağır, Emrah
Biological hydrogen production by purple non-sulfur bacteria is an attractive route to build a large scale hydrogen production system in outdoor natural conditions from various renewable sources. In this study, biological hydrogen production was carried out by agar immobilized purple non-sulfur bacteria in indoor and outdoor conditions. A novel photobioreactor (1.4 L volume) was built and operated continuously for 20 to 64 days in sequential batch mode for long-term hydrogen production using agar-immobilized Rhodobacter capsulatus YO3. The immobilized panel photobioreactor was also operated under natural outdoor conditions to show the feasibility of hydrogen production on a pre-pilot scale. The experiments were carried out in Middle East Technical University, Ankara, Turkey between May and June, 2016. The effects of initial sucrose concentration on hydrogen production, productivity and yield were examined in a long-term operation. Long-term hydrogen production was realized either on sucrose or sugar beet molasses by agar (4% w/v) immobilized Rhodobacter capsulatus YO3. The highest hydrogen yield and hydrogen productivity obtained were 19 mol H2/mol sucrose and 0.73 mmol H2 L-1h-1 in indoors on 5 mM initial sucrose. The effects of higher initial sucrose concentration on hydrogen production were also investigated. The highest hydrogen yield and productivity were 6.1 ± 0.2 mol H2/mol sucrose and 0.87 ± 0.06 mmol H2 L-1h-1, respectively on 10 mM sucrose. The highest hydrogen yield (9.1mol H2/mol sucrose) and productivity (0.64 mmol H2 L-1h-1) were obtained by using sugar beet molasses in indoor conditions. The highest productivity of 0.79±0.04 mmol H2 L-1 h-1 and yield of 5.2±0.4 mol H2/mol sucrose were obtained in outdoors. The present study demonstrated that the immobilized system is feasible for long-term hydrogen production even under varying temperature and illumination. The immobilized system also prevented sudden pH drops by sucrose utilization during the process. Hydrogen production from glucose was carried out as the last part of the study, which was carried out in University of Montreal, Canada. For this purpose, microaerobic dark fermentation was employed to demonstrate and enhance hydrogen production from glucose. Therefore, immobilized cultures of R. capsulatus JP91 and R. palustris CGA009 have been used in single and sequential dark and photofermentative processes. Response surface methodology with the Box-Behnken design was employed to optimize the key parameters such as glucose, inoculum and oxygen concentrations. The highest hydrogen yield and productivity obtained were 7.8 mol H2/mol glucose and 0.15 mmol H2 L-1h-1, respectively by R. capsulatus JP91. These results indicated that biohydrogen production by immobilized purple non-sulfur bacteria is promising particularly for large-scale outdoor natural conditions.


Microarray analysis of the effects of light intensity on hydrogen production metabolism of rhodobacter capsulatus
Gürgan Eser, Muazzez; Yücel, Ayşe Meral; Koku, Harun; Department of Biology (2017)
Biohydrogen generated by purple non-sulfur bacteria is a clean and renewable method of hydrogen production. It can be achieved in outdoor phototobioreactors using the natural sun light in lab to pilot scales. Light is one of the most important parameter affecting hydrogen production in the outdoor condition. Hydrogen productivity may decrease upon light intensity stress by sun light and the diurnal cycle in outdoor conditions. It is important to understand the metabolic response of these bacteria to varying...
Biohydrogen production from barley straw hydrolysate through sequential dark and photofermentation
Ozgur, Ebru; Peksel, Begum (Elsevier BV, 2013-08-01)
Biohydrogen production by sequential operation of dark and photo-fermentation processes is a promising method to produce hydrogen from renewable resources, in a sustainable way. In this study, barley straw hydrolysate (BSEI) dark fermenter effluent (DFE) was used as the biomass feedstock for biohydrogen production through photofermentation. Two different dark fermentation effluents were obtained by performing fermentation with or without addition of yeast extract (YE), using hyperthermophilic dark fermentat...
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...
Photobiological hydrogen production by Rhodobacter sphaeroides O.U.001 by utilization of waste water from milk industry
Turkarslan, S; Yigit, DO; Aslan, K; Eroğlu, İnci; Gündüz, Ufuk (1997-06-26)
Hydrogen production with photosynthetic microorganisms contributes to the protection of the environment, not only in producing a clean fuel but also in waste treatment processes. In this study, Rhodobacter sphaeroides, a photosynthetic bacteria, is used in photobiological hydrogen production by using waste water from the milk industry.
Biohydrogen production from beet molasses by sequential dark and photofermentation
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...
Citation Formats
E. Sağır, “Biohydrogen production by immobilized purple nonsulfur bacteria,” Ph.D. - Doctoral Program, Middle East Technical University, 2018.