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R Zagrodnik, M Łaniecki
Hydrogen production from starch by a co-culture hybrid dark and photofermentation under repeated fed-batch conditions at different organic loading rates (OLR) was studied. Effective cooperation between bacteria in co-culture during initial days was observed at controlled pH 7.0. However, at pH above 6.5 dark fermentation phase was redirected from H2 formation towards production of formic acid, lactic acid and ethanol (which are not coupled with hydrogen production) with simultaneous lower starch removal efficiency...
January 2017: Bioresource Technology
Elisa Corneli, Alessandra Adessi, Federico Dragoni, Giorgio Ragaglini, Enrico Bonari, Roberto De Philippis
The present study was aimed at assessing the biotransformation of dark fermented agroindustrial residues and energy crops for the production of hydrogen and poly-β-hydroxybutyrate (PHB), in lab-scale photofermentation. The investigation on novel substrates for photofermentation is needed in order to enlarge the range of sustainable feedstocks. Dark fermentation effluents of ensiled maize, ensiled giant reed, ensiled olive pomace, and wheat bran were inoculated with Rhodopseudomonas palustris CGA676, a mutant strain suitable for hydrogen production in ammonium-rich media...
September 2016: Bioresource Technology
Anish Ghimire, Serena Valentino, Luigi Frunzo, Francesco Pirozzi, Piet N L Lens, Giovanni Esposito
This work aimed at investigating concomitant production of biohydrogen and poly-β-hydroxybutyrate (PHB) by photofermentation (PF) using dark fermentation effluents (DFE). An adapted culture of Rhodobacter sphaeroides AV1b (pH 6.5, 24±2°C) achieved H2 and PHB yields of 256 (±2) NmLH2/g Chemical Oxygen Demand (COD) and 273.8mgPHB/gCOD (32.5±3% of the dry cells weight (DCW)), respectively. When a diluted (1:2) DFE medium was applied to the adapted pure and mixed photofermentative culture, the respective H2 yields were 164...
October 2016: Bioresource Technology
Alessandra Adessi, Margherita Concato, Andrea Sanchini, Federico Rossi, Roberto De Philippis
Hydrogen represents a possible alternative energy carrier to face the growing request for energy and the shortage of fossil fuels. Photofermentation for the production of H2 constitutes a promising way for integrating the production of energy with waste treatments. Many wastes are characterized by high salinity, and polluted seawater can as well be considered as a substrate. Moreover, the application of seawater for bacterial culturing is considered cost-effective. The aims of this study were to assess the capability of the metabolically versatile freshwater Rhodopseudomonas palustris 42OL of producing hydrogen on salt-containing substrates and to investigate its salt stress response strategy, never described before...
March 2016: Applied Microbiology and Biotechnology
Lilit Gabrielyan, Harutyun Sargsyan, Armen Trchounian
BACKGROUND: Biohydrogen (H2) production by purple bacteria during photofermentation is a very promising way among biological H2 production methods. The effects of protonophores, carbonyl cyanide m-chlorophenylhydrazone (CCCP), 2,4-dinitrophenol (DNP), and inhibitors of enzymes, involved in H2 metabolism, metronidazole (Met), diphenyleneiodonium (DPI), and dimethylsulphoxide (DMSO) on H2 production by Rhodobacter sphaeroides MDC6522 isolated from Jermuk mineral springs in Armenia have been investigated in both nitrogen-limited and nitrogen-excess conditions...
2015: Microbial Cell Factories
R Zagrodnik, M Laniecki
The role of pH control on biohydrogen production by co-culture of dark-fermentative Clostridium acetobutylicum and photofermentative Rhodobacter sphaeroides was studied. Single stage dark fermentation, photofermentation and hybrid co-culture systems were studied at different values of controlled and uncontrolled pH. Increasing pH during dark fermentation resulted in lower hydrogen production rate (HPR) and longer lag time for both controlled and uncontrolled conditions. However, it only slightly affected cumulative H2 volume...
October 2015: Bioresource Technology
Basar Uyar, Muazzez Gürgan, Ebru Özgür, Ufuk Gündüz, Meral Yücel, Inci Eroglu
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...
October 2015: Bioprocess and Biosystems Engineering
Rosangela Lucio Costa, Thamayne Valadares Oliveira, Juliana de Souza Ferreira, Vicelma Luiz Cardoso, Fabiana Regina Xavier Batista
The most important global demand is the energy supply from alternative source. Ethanol may be considered an environmental friendly fuel that has been produced by feedstock. The production of ethanol by microalgae represent a process with reduced environmental impact with efficient CO2 fixation and requiring less arable land. This work studied the production of ethanol from green alga Chlamydomonas reinhardtii through the cellular metabolism in a light/dark cycle at 25 °C in a TAP medium with sulfur depletion...
April 2015: Bioresource Technology
L Dipasquale, A Adessi, G d'Ippolito, F Rossi, A Fontana, R De Philippis
Two-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO2-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T...
January 2015: Applied Microbiology and Biotechnology
Yuan Liu, Dipankar Ghosh, Patrick C Hallenbeck
A future hydrogen economy requires the sustainable production of renewable hydrogen. One method to produce hydrogen from stored renewable energy could be through reformation of bioethanol. However, chemically catalyzed reformation processes, although well studied, still present a number of significant technical challenges. Here, bioreformation of ethanol to hydrogen by photofermentation with the photosynthetic bacterium Rhodopseudomonas palustris is described. Cultures were shown to tolerate up to 2% ethanol...
January 2015: Bioresource Technology
Alberto Scoma, Lorenzo Durante, Lorenzo Bertin, Fabio Fava
In anaerobiosis, the microalga Chlamydomonas reinhardtii is able to produce H2 gas. Electrons mainly derive from mobilization of internal reserves or from water through biophotolysis. However, the exact mechanisms triggering this process are still unclear. Our hypothesis was that, once a proper redox state has been achieved, H2 production is eventually observed. To avoid nutrient depletion, which would result in enhanced fermentative pathways, we aimed to induce long-lasting H2 production solely through a photosynthesis : respiration equilibrium...
December 2014: New Phytologist
Ahmed Tawfik, Haitham El-Bery, Sheena Kumari, Faizal Bux
Hydrogen production (HP) from dark fermentation effluent of starch wastewater via vertical tubular photo-bioreactor was investigated. The reactor was inoculated with mixed culture of bacteria and operated at light intensity of 190 W/m(2). Hydraulic retention time (HRT) and organic loading rate (OLR) was varied between 0.9 to 4.0 h and 3.2 to 16 g COD/l.d., respectively. Increasing the HRT from 0.9 to 2.5 h, significantly (P<0.05) increased HP from 1±0.04 to 3.05±0.19 l/d, respectively. However, minimal increase in HP occurred when increasing the HRT up to 4...
September 2014: Bioresource Technology
Héctor M Poggi-Varaldo, Karla M Munoz-Paez, Carlos Escamilla-Alvarado, Paula N Robledo-Narváez, M Teresa Ponce-Noyola, Graciano Calva-Calva, Elvira Ríos-Leal, Juvencio Galíndez-Mayer, Carlos Estrada-Vázquez, Alfredo Ortega-Clemente, Noemí F Rinderknecht-Seijas
Biohydrogen is a sustainable form of energy as it can be produced from organic waste through fermentation processes involving dark fermentation and photofermentation. Very often biohydrogen is included as a part of biorefinery approaches, which reclaim organic wastes that are abundant sources of renewable and low cost substrate that can be efficiently fermented by microorganisms. The aim of this work was to critically assess selected bioenergy alternatives from organic solid waste, such as biohydrogen and bioelectricity, to evaluate their relative advantages and disadvantages in the context of biorefineries, and finally to indicate the trends for future research and development...
May 2014: Waste Management & Research
Ao Xia, Jun Cheng, Lingkan Ding, Richen Lin, Rui Huang, Junhu Zhou, Kefa Cen
The effects of pre-treatment methods on saccharification and hydrogen fermentation of Chlorella pyrenoidosa biomass were investigated. When raw biomass and biomass pre-treated by steam heating, by microwave heating, and by ultrasonication were used as feedstock, the hydrogen yields were only 8.8-12.7 ml/g total volatile solids (TVS) during dark fermentation. When biomass was pre-treated by steam heating with diluted acid and by microwave heating with diluted acid, the dark hydrogen yields significantly increased to 75...
October 2013: Bioresource Technology
Ao Xia, Jun Cheng, Richen Lin, Hongxiang Lu, Junhu Zhou, Kefa Cen
The thermodynamic comparison in dark fermentation between amino acids and reducing sugars released from Nannochloropsis oceanica biomass are investigated for the first time. The total utilisation efficiencies of amino acids and reducing sugars are both about 95% in dark fermentation. But the consumption time of most amino acids is about 2 times as long as that of most reducing sugars in dark fermentation. A three-stage method comprising dark fermentation, photofermentation and methanogenesis is proposed to improve hydrogen and energy yields from N...
June 2013: Bioresource Technology
Robert W M Pott, Christopher J Howe, John S Dennis
The growth of the biodiesel industry, and its concurrent production of glycerol, has lowered the price of glycerol 20-fold. While many options for using this glycerol have been proposed, the size of the waste stream means that generation of fuels is likely to be the only viable route. One such fuel is hydrogen, production of which can be achieved biologically. The photofermentation of glycerol to hydrogen using Rhodopseudomonas palustris was investigated by exploring the growth rate, hydrogen production rate and hydrogen yield...
February 2013: Bioresource Technology
Mona Abo-Hashesh, Nicolas Desaunay, Patrick C Hallenbeck
Photofermentative hydrogen (H(2)) production from glucose with the photosynthetic bacterium Rhodobacter capsulatus JP91 (hup(-)) was examined using a photobioreactor operated in continuous mode. Stable and high hydrogen yields on glucose were obtained at three different retention times (HRTs; 24, 48 and 72 h). The H(2) production rates, varying between 0.57 and 0.81 mmol/h, and optical densities (OD(600 nm)) were similar for the different HRTs examined. However, the rate of glucose consumption was influenced by HRT being greater at HRT 24h than HRTs 48 and 72 h...
January 2013: Bioresource Technology
Dipankar Ghosh, Irma Flore Sobro, Patrick C Hallenbeck
Hydrogen production from glucose via single-stage photofermentation was examined with the photosynthetic bacterium Rhodobacter capsulatus JP91 (hup-). Response surface methodology with Box-Behnken design was used to optimize the independent experimental variables of glucose concentration, glutamate concentration and light intensity, as well as examining their interactive effects for maximization of molar hydrogen yield. Under optimal condition with a light intensity of 175W/m(2), 35mM glucose, and 4.5mM glutamate, a maximum hydrogen yield of 5...
November 2012: Bioresource Technology
Mark D Redwood, Rafael L Orozco, Artur J Majewski, Lynne E Macaskie
An Integrated Biohydrogen Refinery (IBHR) and experimental net energy analysis are reported. The IBHR converts biomass to electricity using hydrothermal hydrolysis, extractive biohydrogen fermentation and photobiological hydrogen fermentation for electricity generation in a fuel cell. An extractive fermentation, developed previously, is applied to waste-derived substrates following hydrothermal pre-treatment, achieving 83-99% biowaste destruction. The selective separation of organic acids from waste-fed fermentations provided suitable substrate for photofermentative hydrogen production, which enhanced the gross energy generation up to 11-fold...
September 2012: Bioresource Technology
Jung-Yeol Lee, Xue-Jiao Chen, Eun-Jung Lee, Kyung-Sok Min
To improve the hydrogen yield from biological fermentation of organic wastewater, a co-culture system of dark- and photo-fermentation bacteria was investigated. In a pureculture system of the dark-fermentation bacterium Clostridium butyricum, a pH of 6.25 was found to be optimal, resulting in a hydrogen production rate of 18.7 ml-H₂/l/h. On the other hand, the photosynthetic bacterium Rhodobacter sphaeroides could produce the most hydrogen at 1.81 mol-H₂/mol-glucose at pH 7.0. The maximum specific growth rate of R...
March 2012: Journal of Microbiology and Biotechnology
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