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1.
Dominic Deo Androga Ebru Özgür Inci Eroglu Ufuk Gündüz Meral Yücel 《International Journal of Hydrogen Energy》2012
One of the challenges in the development of integrated dark and photofermentative biological hydrogen production systems is the presence of ammonium ions in dark fermentation effluent (DFE). Ammonium strongly inhibits the sequential photofermentation process, and so its removal is required for successful process integration. In this study, the removal of ammonium ions from molasses DFE using a natural zeolite (clinoptilolite) was investigated. The samples were treated with batch suspensions of Na-form clinoptilolite. The ammonium ion concentration could be reduced from 7.60 mM to 1.60 mM and from 12.30 mM to 2.40 mM for two different samples. Photofermentative hydrogen production on treated and untreated molasses DFE samples were investigated in batch photobioreactors by an uptake hydrogenase deleted (hup−) mutant strain of Rhodobacter capsulatus. Maximum hydrogen productivities of 1.11 mmol H2/Lc·h and 1.16 mmol H2/Lc·h and molar yields of 79% and 90% were attained in the treated DFE samples, while the untreated samples resulted in no hydrogen production. The results showed that ammonium ions in molasses DFE could be effectively removed using clinoptilolite by applying a cost-effective, simple batch process. 相似文献
2.
Ebru Özgür Astrid E. Mars Begüm Peksel Annemarie Louwerse Meral Yücel Ufuk Gündüz Pieternel A.M. Claassen İnci Eroğlu 《International Journal of Hydrogen Energy》2010
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 the photofermentation. C. saccharolyticus was grown in a pH-controlled bioreactor, in batch mode, on molasses with an initial sucrose concentration of 15 g/L. The influence of additions of NH4+ and yeast extract on sucrose consumption and hydrogen production was determined. The highest hydrogen yield (4.2 mol of H2/mol sucrose) and maximum volumetric productivity (7.1 mmol H2/Lc.h) were obtained in the absence of NH4+. The effluent of the dark fermentation containing no NH4+ was fed to a photobioreactor, and hydrogen production was monitored under continuous illumination, in batch mode. Productivity and yield were improved by dilution of the dark fermentor effluent (DFE) and the additions of buffer, iron-citrate and sodium molybdate. The highest hydrogen yield (58% of the theoretical hydrogen yield of the consumed organic acids) and productivity (1.37 mmol H2/Lc.h) were attained using the hup− mutant of R. capsulatus. The overall hydrogen yield from sucrose increased from the maximum of 4.2 mol H2/mol sucrose in dark fermentation to 13.7 mol H2/mol sucrose (corresponding to 57% of the theoretical yield of 24 mol of H2/mole of sucrose) by sequential dark and photofermentation. 相似文献
3.
Based on the generation of Pantoea agglomerans BH18 library using Tn7 transposon system, mutant screens were conducted for improvement the ability of hydrogen production of this strain. These mutants were used to test for ability of hydrogen production in the initial pH of 5.0. In contrast to wild type strain BH18, a transposon mutant, named as strain TB108, was screened for high hydrogen-producing capability and acid tolerance in the initial pH of 5.0. The factors required for hydrogen production of the aciduric transposon-mutagenized strain TB108 were determined. The mutant strain TB108 similar as wild type strain BH18 was able to produce hydrogen over a wide range of salt concentration from 0.4% to 6%. Under the marine conditions with the initial pH of 5.0 and glucose concentration of 10 g/L, the total hydrogen production of the mutant TB108 was (1.36 ± 0.04) mol H2/mol glucose (mean ± S.E.), increasing by 55% compared with wild type. In addition, the mutant strain TB108 could produce hydrogen using many carbon sources such as fructose, glucose, sucrose, sorbitol and so on. This result demonstrated that the mutant strain with high acid tolerance is beneficial for improvement of hydrogen production. 相似文献
4.
The production of biohydrogen via photofermentation has been shown to have a low environmental impact and can often be integrated into wastewater treatment systems. However, currently, photofermentation has low production rates in comparison to industrial hydrogen production processes, and therefore requires improvement. One route for enhancing hydrogen productivity is the development of improved photobioreactor (PBR) systems. The aim of this study was to compare the hydrogen productivity of Rhodopseudomonas palustris under planktonic, and immobilized cell conditions, with the reactor operating either as a packed bed or a fluidized bed. The fluidized bed PBR achieved a maximum specific hydrogen production rate and substrate conversion efficiency of 15.74 ± 2.2 mL/g/h and 43% respectively, outperforming the conventional planktonic culture and the packed bed PBR. This work demonstrates a significant improvement in productivity over planktonic photofermentation, as well as demonstrating the use of immobilized cells under reactor conditions not usually associated with photosynthetic systems. 相似文献
5.
Rodolfo García-Sánchez Roberto Ramos-Ibarra Guadalupe Guatemala-Morales Enrique Arriola-Guevara Guillermo Toriz-González Rosa Isela Corona-González 《International Journal of Hydrogen Energy》2018,43(33):15857-15869
Hydrogen production by photofermentation of tequila vinasses (VT) was studied using Rhodopseudomonas pseudopalustris DSM 123. To the best of our knowledge this is the first report on hydrogen production by photofermentation on VT. Hydrogen production was doubled on VT (260 m$props_value{literPattern}/L) as compared to a synthetic medium. Storing VT changed its chemical composition; however, in photofermentations of a sixty-day old stock, growth and hydrogen production were similar to fresh VT. The periodic displacement of hydrogen with nitrogen resulted in a three-fold increase in both hydrogen and growth of R. pseudopalustris (860 mL H2/L and 4.5 g/L respectively) as compared to non-displaced headspace. Hydrogen almost doubled at a light intensity of 270 W/m2 (2249 mL H2) as compared to 68 W/m2. In dark-light cycles, biomass and hydrogen production were highest with continuous illumination. The potential of VT to produce hydrogen in high amounts using R. pseudopalustris has been demonstrated. 相似文献
6.
Nilüfer AfsarEbru Özgür Muazzez GürganSevilay Akköse Meral YücelUfuk Gündüz Inci Eroglu 《International Journal of Hydrogen Energy》2011,36(1):432-438
Hydrogen productivities of different photosynthetic bacteria have been searched on real thermophilic dark fermentation effluents (DFE). The results obtained with potato steam peels hydrolysate (PSP) DFE were compared to glucose DFE. Photobiological hydrogen production has been carried out in indoor, batch photobioreactors using several strains of purple non-sulfur (PNS) bacteria such as Rhodobacter capsulatus (DSM1710), Rhodobacter capsulatus hup- (YO3), Rhodobacter sphaeroides O.U.001 (DSM5864), Rb. sphaeroides O.U.001 hup- and Rhodopseudomonas palustris.The efficiency of photofermentation depends highly on the composition of the effluent and the PNS bacterial strain used. Rb. sphaeroides produced the highest amount of hydrogen on glucose DFE. Rb. capsulatus gave better results on PSP DFE. This study demonstrates that photobiological hydrogen production with high efficiency and productivity is possible on thermophilic dark fermentation effluents. Consequently, a sequential operation of dark fermentation and photofermentation is a promising route to produce hydrogen, and it provides a higher hydrogen yield compared to single step processes. 相似文献
7.
Pantoea agglomerans BH18, isolated from mangrove sludge, could produce hydrogen under marine culture condition. To improve the hydrogen-producing capacity of this strain, we constructed a stable transposon-mutagenized library of P. agglomerans BH18. A Tn7-based transposon was randomly inserted into genomic DNA of P. agglomerans BH18. Mutants were identified by kanamycin resistance and amplification of the inserted transposon sequences. A transposon mutant, named as strain TB212, was screened for the highest hydrogen production ability. The total volume of hydrogen gas evolved by this mutant strain TB212 was 60% higher than that of the wild type. The mutant strain TB212 was able to produce hydrogen over a wide range of initial pH from 5.0 to 10.0, with an optimum initial pH of 7.0, and hydrogen production was 2.52 ± 0.02 mol H2/mol glucose (mean ± S.E.) under marine culture condition. The mutant strain TB212 could produce hydrogen at the salt concentration from 3 to 6%. It was concluded that the transposon-mutagenized library may be a useful tool for investigation of high efficiency hydrogen-producing bacteria. 相似文献
8.
An NADH dehydrogenase encoded by the nuo cluster was isolated and impaired by knocking out the nuoB gene in Enterobacter aerogenes to examine its effect on hydrogen production. Three nuoB-deleted mutant strains were constructed from the wild-type strain E. aerogenes IAM1183 and two recombinant strains, IAM1183-A (ΔhycA) and IAM1183-O (ΔhybO), from which the hycA and hybO genes had already been deleted previously, respectively. Compared with the performance of the wild-type strain, the overall hydrogen production of the mutants IAM1183-B (ΔnuoB), IAM1183-AB (ΔhycA/ΔnuoB) and IAM1183-BO (ΔhybO/ΔnuoB) was increased by 49.2%, 54.0%, and 52.4% in batch culture, respectively. The hydrogen yields from glucose by the three mutants IAM1183-B, IAM1183-AB, IAM1183-BO were 1.38, 1.49, and 1.39 mol H2/mol glucose, respectively, while it was 1.16 mol H2/mol glucose in the wild-type strain. Metabolic flux analysis indicated that all three mutants exhibited reduced fluxes to lactate production, and enhanced fluxes toward the generation of hydrogen, acetate, ethanol, succinate and 2,3-butanediol. Both the formate pathway and the NADH pathway contributed to increased hydrogen production in the mutant strains. The assay of 4 NADH-mediated enzyme activities (H2ase, LDH, ADH and BDDH) was in accordance with the redistributions of the metabolic fluxes in the mutant strains. 相似文献
9.
Rathnasiri G. Puhulwella Laurent Beckers Frank Delvigne Alina S. Grigorescu Philippe Thonart Serge Hiligsmann 《International Journal of Hydrogen Energy》2014
This study investigates the mesophilic biohydrogen production from glucose using a strictly anaerobic strain, Clostridium butyricum CWBI1009, immobilized in a trickling bed sequenced batch reactor (TBSBR) packed with a Lantec HD Q-PAC® packing material (132 ft2/ft3 specific surface). The reactor was operated for 62 days. The main parameters measured here were hydrogen composition, hydrogen production rate and soluble metabolic products. pH, temperature, recirculation flow rate and inlet glucose concentration at 10 g/L were the controlled parameters. The maximum specific hydrogen production rate and the hydrogen yield found from this study were 146 mmol H2/L.d and 1.67 mol H2/mol glucose. The maximum hydrogen composition was 83%. Following a thermal treatment, the culture was active without adding fresh inoculum in the subsequent feeding and both the hydrogen yield and the hydrogen production rate were improved. For all sequences, the soluble metabolites were dominated by the presence of butyric and acetic acids compared to other volatile fatty acids. The results from the standard biohydrogen production (BHP) test which was conducted using samples from TBSBR as inoculum confirmed that the culture generated more biogas and hydrogen compared to the pure strain of C. butyricum CWBI1009. The effect of biofilm activity was studied by completely removing (100%) the mixed liquid and by adding fresh medium with glucose. For three subsequent sequences, similar results were recorded as in the previous sequences with 40% removal of spent medium. The TBSBR biofilm density varied from top to bottom in the packing bed and the highest biofilm density was found at the bottom plates. Moreover, no clogging was evidenced in this packing material, which is characterized by a relatively high specific surface area. Following a PCA test, contaminants of the Bacillus genus were isolated and a standard BHP test was conducted, resulting in no hydrogen production. 相似文献
10.
Anjana Pandey Pallavi Sinha Ashutosh Pandey 《International Journal of Hydrogen Energy》2021,46(10):7137-7146
Microalgae and cyanobacteria can be used as a potential biomass to produce hydrogen from stored glycogen and starch through fermentation and photofermentation. In this study, the potential of algal biomass i.e. Spirulina platensis hydrolysate as a substrate for sequential fermentative (I-stage) and photo-fermentative (II-stage) biohydrogen production was evaluated. Response Surface Methodology (RSM) was employed to find the optimum photofermentation conditions. From the preliminary optimization experiments, it was found that the significantly affecting factors for H2 production were pH, dilution fold (D.F.) of fermentate and Fe(II) sulfate concentration during photofermentation (second stage). In the present study, 1% (w/v) Spirulina platensis hydrolyzate produced 23.06 ± 3.63 mmol of H2 with yield of 1.92 ± 0.20 mmol H2/g COD reduced. In the second stage experiment 1510 ± 35 mL/l hydrogen was produced using inoculum volume-20.0% (v/v) and inoculum age-48 h of co-culture of Rhodobacter sphaeroides NMBL-01 and Bacillus firmus NMBL-03 under conditions pH-5.95, D.F. of dark fermentate-20.30 folds, Fe(II) sulfate concentration-0.412 μM, temperature-32±2 °C and light intensity-2.5 klux. 相似文献
11.
《International Journal of Hydrogen Energy》2019,44(31):16199-16211
The biological H2 production industry would be independent from other industries if it has its own supply of organic materials especially in non-agricultural countries. In this study, acid hydrolyzed biomass of the potent extracellular polysaccharides (EPSs) producing cyanobacterium Nostoc commune and glycogen (as intracellular polysaccharide) enriched Anabaena variabilis NIES-2095 were used as a cheap organic carbon feedstock for biological H2 production by two stages dark fermentation by Escherichia coli strain MWW and Clostridium acetobutylicum DSM-792 or Clostridium beijerinckii DSM-1820 and photofermentation by Rhodobacter capsulatus JCM-21090 under anaerobic conditions. Acid hydrolysis of air dried cyanobacterial biomass was conducted at optimum conditions of 4 M HCl at 120 °C in an autoclave for 30 min and subsequently neutralized and used as an organic carbon source for first stage dark fermentation followed by a second stage photofermentation. The facultative anaerobe Escherichia coli strain MWW was used for maintaining anaerobiosis. Escherichia coli strain MWW was isolated and identified by morphological and biochemical characterizations as well as molecular biological phylogenetic analysis of its 16S rDNA sequence. Nostoc commune was identified by morphological and microscopic characterizations and by 16S rDNA sequence phylogenetic analysis. The two stages dark fermentation by Escherichia coli and Clostridium acetobutylicum or Clostridium beijerinckii and photofermentation by Rhodobacter capsulatus produced in total 5.9 and 5.6 mol H2/mole reducing sugars of acid hydrolyzed Nostoc commune EPSs/biomass, respectively and 5.43 and 5 mol H2/mole reducing sugars of acid hydrolyzed biomass of glycogen enriched Anabaena variabilis, respectively. These results indicate a high potency of using cyanobacterial polysaccharides/biomass (extracellular polysaccharides and intracellular glycogen) as an organic carbon source for H2 production which would be of importance for non-agricultural countries. 相似文献
12.
Yong-Zhong Wang Qiang Liao Xun Zhu Jun Li Duu-Jong Lee 《International Journal of Hydrogen Energy》2011,36(21):14004-14013
Biochemical kinetic characteristics of photo-fermentative hydrogen production were experimentally and numerically investigated to optimize the photo-fermentation hydrogen-producing process in this work. It is found that a maximum specific growth rate of 0.26 h−1 was achieved under the optimal conditions of illumination intensity 6000 lux, 30 °C culture temperature and pH 7.0 of culture medium. These experimental results also led to an empirical formula of the maximum specific microbial growth rate (μmax) as a function of illumination intensity, pH and temperature. With the empirical formula, the modified Monod equation along with the kinetic equations for biomass growth, glucose consumption and hydrogen production is then developed to simulate the photofermentation hydrogen-producing process. The modeling results are in good agreements with the experimental data, indicating that the developed kinetic models are able to objectively describe the characteristics of hydrogen production by PSB under different culture conditions. 相似文献
13.
Chuannan Long Jingjing Cui Zuotao Liu Yuntao Liu Minnan Long Zhong Hu 《International Journal of Hydrogen Energy》2010
Statistical experimental designs were applied for the optimization of medium constituents for hydrogen production from xylose by newly isolated Enterobacter sp. CN1. Using Plackett–Burman design, xylose, FeSO4 and peptone were identified as significant variables which highly influenced hydrogen production. The path of steepest ascent was undertaken to approach the optimal region of the three significant factors. These variables were subsequently optimized using Box–Behnken design of response surface methodology (RSM). The optimum conditions were found to be xylose 16.15 g/L, FeSO4 250.17 mg/L, peptone 2.54 g/L. Hydrogen production at these optimum conditions was 1149.9 ± 65 ml H2/L medium. Under different carbon sources condition, the cumulative hydrogen volume were 1217 ml H2/L xylose medium, 1102 ml H2/L glucose medium and 977 ml H2/L sucrose medium; the maximum hydrogen yield were 2.0 ± 0.05 mol H2/mol xylose, 0.64 mol H2/mol glucose. Fermentative hydrogen production from xylose by Enterobacter sp. CN1 was superior to glucose and sucrose. 相似文献
14.
Peyman Abdeshahian Najeeb Kaid Nasser Al-Shorgani Noura K.M. Salih Hafiza Shukor Abudukeremu Kadier Aidil Abdul Hamid Mohd Sahaid Kalil 《International Journal of Hydrogen Energy》2014
In view of increasing attempts for the production of renewable energy, the production of biohydrogen energy by a new mesophilic bacterium Clostridium sp. YM1 was performed for the first time in the dark fermentation. Experimental results showed that the fermentative hydrogen was successfully produced by Clostridium sp. YM1 with the highest cumulative hydrogen volume of 3821 ml/L with a hydrogen yield of 1.7 mol H2/mol glucose consumed. Similar results revealed that optimum incubation temperature and pH value of culture medium were 37 °C and 6.5, respectively. The study of hydrogen production from glucose and xylose revealed that this strain was able to generate higher hydrogen from glucose compared to that from xylose. The profile of volatile fatty acids produced showed that hydrogen generation by Clostridium sp. YM1 was butyrate-type fermentation. Moreover, the findings of this study indicated that an increase in head space of fermentation culture positively enhanced hydrogen production. 相似文献
15.
Irina Harun Jamaliah Md Jahim Nurina Anuar Osman Hassan 《International Journal of Hydrogen Energy》2012
Two out of six bacterial isolates obtained from the guts of Globitermes sp. termites were identified as hydrogen-producing bacteria. One isolate, Enterobacter cloacae KBH3, was characterised using the BIOLOG identification system and 16S rRNA gene analysis. In a batch fermentation study to evaluate its growth in defined medium, E. cloacae KBH3 produced 154 ml H2 per litre medium with approximately 50% hydrogen content. The carbon utilisation results suggest that E. cloacae KBH3 have the potential to be a good hydrogen producer. This strain is also able to produce hydrogen within a wide range of temperatures (28–40 °C) and pH (4.5–8). In several fermentation runs, the pH of the culture dropped from 6.5 to 5.36 within the first 3 h, which was mostly due to the biosynthesis of formate. An increase of cumulative hydrogen production was recorded as well as a decrease in the concentration of formate, indicating the importance of the formate pathway for hydrogen production. The highest rate of hydrogen production of 180.74 ml H2/l/h was achieved when lactate and acetate were at their highest concentrations. Most of the hydrogen gas was produced during the exponential growth phase, and the biogas continued to be produced during the stationary phase. The specific growth rate was calculated to be 0.224 per hour while the hydrogen yield was 1.8 mol of hydrogen per mol of glucose. At the end of the batch study, the highest cumulative hydrogen production was 2404 ml H2 per litre of fermentation medium. 相似文献
16.
《International Journal of Hydrogen Energy》2023,48(77):29916-29927
NifA is the primary activator of nitrogenase, and the N-terminal domain of nifA is sensitive to ammonium concentration. In this work, a mutant Rhodobacter capsulatus ZX01 with a genetically engineered deletion in the N-terminal region of nifA1 was constructed by employing overlap extension PCR to mitigate the inhibition of ammonium on nitrogenase expression in photosynthetic bacteria. The effects of different ammonium ion concentrations on the growth and photo-fermentative hydrogen production performance of wild-type strain R. capsulatus SB1003 and mutant ZX01 with glucose and volatile fatty acids as the carbon sources were studied, respectively. When the ratio of NH4+-N was 20% and 30%, the hydrogen yield of the mutant ZX01 was enhanced by 14.8% and 20.9% compared with that of R. capsulatus SB1003 using 25 mM acetic acid and 34 mM butyric acid as the carbon source, respectively. In comparison, using 30 mM glucose as the carbon source, the hydrogen yield of ZX01 was increased by 17.7% and 22.2% compared with that of R. capsulatus SB1003 when the ratio of NH4+-N was 20% and 30%, and the nitrogenase activity of ZX01 was also enhanced by 38.0% and 47.6%, respectively. When using 10 mM NH4+ as a single nitrogen source, ZX01 showed a 2.6-fold increase in H2 production. These results indicated that ZX01 demonstrated higher ammonium tolerance and better hydrogen production performance than the wild-type. The deletion in the N-terminal region of nifA1 could partially de-repress the nitrogenase activity inhibited by ammonium. 相似文献
17.
Lijing Jiang Chuannan Long Xiaobing Wu Hongxiu Xu Zongze Shao Minnan Long 《International Journal of Hydrogen Energy》2014
A unique thermophilic fermentative hydrogen-producing strain H53214 was isolated from a deep-sea hydrothermal vent environment, and identified as Caloranaerobacter azorensis based on bacterial 16S rRNA gene analysis. The optimum culture condition for hydrogen production by the bacterium, designated C. azorensis H53214, was investigated by the response surface methodology (RSM). Eight variables including the concentration of NaCl, glucose, yeast, tryptone, FeSO4 and MgSO4, initial pH and incubation temperature were screened based on the Plackett–Burman design. The results showed that initial pH, tryptone and yeast were significant variables, which were further optimized using the steepest ascent method and Box–Behnken design. The optimal culture conditions for hydrogen production were an initial pH of 7.7, 8.3 g L−1 tryptone and 7.9 g L−1 yeast. Under these conditions, the maximum cumulative hydrogen volume, hydrogen yield and maximum H2 production rate were 1.58 L H2 L−1 medium, 1.46 mol H2 mol−1 glucose and 25.7 mmol H2 g−1 cell dry weight (CDW) h−1, respectively. By comparison analysis, strain H53214 was superior to the most thermophilic hydrogen producers because of the high hydrogen production rate. In addition, the isolation of C. azorensis H53214 indicated the deep-sea hydrothermal environment might be a potential source for fermentative hydrogen-producing thermophiles. 相似文献
18.
The effect of culture parameters on hydrogen production using strain GHL15 in batch culture was investigated. The strain belongs to the genus Thermoanaerobacter with 98.9% similarity to Thermoanaerobacter yonseiensis and 98.5% to Thermoanaerobacter keratinophilus with a temperature optimum of 65–70 °C and a pH optimum of 6–7. The strain metabolizes various pentoses, hexoses, and disaccharides to acetate, ethanol, hydrogen, and carbon dioxide. However substrate inhibition was observed above 10 mM glucose concentration. Maximum hydrogen yields on glucose were 3.1 mol H2 mol−1 glucose at very low partial pressure of hydrogen. Hydrogen production from various lignocellulosic biomass hydrolysates was investigated in batch culture. Various pretreatment methods were examined including acid, base, and enzymatic (Celluclast® and Novozyme 188) hydrolysis. Maximum hydrogen production (5.8–6.0 mmol H2 g−1 dw) was observed from Whatman paper (cellulose) hydrolysates although less hydrogen was produced by hydrolysates from other examined lignocellulosic materials (maximally 4.83 mmol H2 g−1 dw of grass hydrolysate). The hydrogen yields from all lignocellulosic hydrolysates were improved by acid and alkaline pretreatments, with maximum yields on grass, 7.6 mmol H2 g−1 dw. 相似文献
19.
Ruofan WangWenming Zong Changli QianYongjun Wei Ruisong Yu Zhihua Zhou 《International Journal of Hydrogen Energy》2011,36(19):12159-12167
Clostridium perfringens strain W11, which we previously identified as the major hydrogen producer in a hydrogen-producing microbial flora, was isolated in this study. The hydrogen yield from sucrose of this strain was 1.53 mol H2/mol hexose. To exclude potential safety problems, the plc gene, encoding an alpha toxin protein, was permanently knocked out using the Targetron gene knockout system, creating strain W12. Strains W11 and W12 both produced lactate, acetate, and butyrate during hydrogen production. Furthermore, yields of these metabolites and hydrogen were near-identical by the two strains. When the ldh gene encoding lactate dehydrogenase in strain W12 was deleted, the hydrogen yield and acetate and butyrate concentrations in the resulting mutant, W13, increased by 51%, 26%, and 57%, respectively. Lactate production by strain W13 decreased almost to zero. The growth rates of the wild-type strain W11 and its mutant derivatives were similar. 相似文献
20.
Nan Mei Nesrine Zergane Anne Postec Gael Erauso Angélique Ollier Claude Payri Bernard Pelletier Marie-Laure Fardeau Bernard Ollivier Marianne Quéméneur 《International Journal of Hydrogen Energy》2014
The hydrogen-producing strain PROH2 pertaining to the genus Clostridium was successfully isolated from a shallow submarine hydrothermal chimney (Prony Bay, New Caledonia) driven by serpentinization processes. Cell biomass and hydrogen production performances during fermentation by strain PROH2 were studied in a series of batch experiments under various conditions of pH, temperature, NaCl and glucose concentrations. The highest hydrogen yield, 2.71 mol H2/mol glucose, was observed at initial pH 9.5, 37 °C, and glucose concentration 2 g/L, and was comparable to that reported for neutrophilic clostridial species. Hydrogen production by strain PROH2 reached the maximum production rate (0.55 mM-H2/h) at the late exponential phase. Yeast extract was required for growth of strain PROH2 and improved significantly its hydrogen production performances. The isolate could utilize various energy sources including cellobiose, galactose, glucose, maltose, sucrose and trehalose to produce hydrogen. The pattern of end-products of metabolism was also affected by the type of energy sources and culture conditions used. These results indicate that Clostridium sp. strain PROH2 is a good candidate for producing hydrogen under alkaline and mesothermic conditions. 相似文献