A Study on the Role of Clostridium Saccharoperbutylacetonicum N1-4 (ATCC 13564) in Producing Fermentative Hydrogen (original) (raw)
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World Journal of Microbiology and Biotechnology, 2005
Various medium components (carbon and nitrogen sources, iron, inoculum size) and environmental factors (initial pH and the agitation speed) were evaluated for their effects on the rate and the yield of hydrogen production by Clostridium saccharoperbutylacetonicum. Among the carbon sources assessed, cells grown on disaccharides (lactose, sucrose and maltose) produced on the average more than twice (2.81 mol-H 2 /mol sugar) as much hydrogen as monosaccharides (1.29 mol-H 2 /mol sugar), but there was no correlation between the carbon source and the production rate. The highest yield (2.83 mol/mol) was obtained in lactose and sucrose but the highest production rate (1.75 mmol/h) in sucrose. Using glucose as carbon source, yeast extract was the best nitrogen source. A parallel increase between the production rate and the yield was obtained by increasing glucose concentration up to 40 g/l (1.76 mol-H 2 /mol, 3.39 mmol/h), total nitrogen as yeast extract up to 0.1% (1.41 mol/mol, 1.91 mmol/h) and agitation up to 100 rev/min (1.66 mol-H 2 /mol, 1.86 mmol/h). On the other hand, higher production rates were favoured in preference to the yield at a neutral initial pH 7 (2.27 mmol/h), 1000 mg iron/l or more (1.99 mmol/h), and a larger inoculum size, 10%, (2.36 mmol/h) whereas an initial alkaline pH of 8.5 (1.72 mol/mol), a lower iron concentration of 25 mg/l (1.74 mol/mol) and smaller inoculum size, 1%, (1.85 mol/mol) promoted higher yield over production rate.
Experimental Study of Bio-Hydrogen Production by Clostridium beijerinckii from Different Substrates
Energies
Glucose, alcohol stillage and glycerol were used as substrates for bio-hydrogen production by the newly isolated strain Clostridium beijerinckii 6A1 under batch conditions. High molar yields of hydrogen from the studied organic substrates were observed. There was a neat difference in the metabolic pathways of substrate digestion when hexose-based substrate or glycerol were used. The products of glycerol digestion showed that a pathway with no formic acid formation as intermediate was probable. In this case, considerable concentrations of acetic and propionic acid (up to 6 g dm−3) and small amounts of butanol were observed after 48 h. When glucose or hexose-based substrates were used, considerable amounts of formic acid (up to 6 g dm−3), i.e., the pathway proposed for Clostridia mixed cultures, were appropriate for the observed process of hydrogen release. For these substrates, considerable amounts of propionic acid in concentrations up to 1 g dm−3 were observed. That is why the path...
Biotechnology and Bioprocess Engineering, 2008
The optimum conditions for biological hydrogen production from food waste by Clostridium beijerinckii KCTC 1875 were investigated. The optimum initial pH and fermentation temperature were 7.0 and 40°C, respectively. When the pH of fermentation was controlled to 5.5, a maximum amount of hydrogen could be obtained. Under these conditions, about 2,737 mL of hydrogen was produced from 50 g COD/L of food waste for 24 h, and the hydrogen content in the biogas was 38%. Hydrogen production rate and yield were about 108 mL/L·h and 128 mL/g CODdegraded, respectively. High concentrations of acetic (
Improvement of fermentative hydrogen production: various approaches
Applied Microbiology and Biotechnology, 2004
Fermentation of biomass or carbohydrate-based substrates presents a promising route of biological hydrogen production compared with photosynthetic or chemical routes. Pure substrates, including glucose, starch and cellulose, as well as different organic waste materials can be used for hydrogen fermentation. Among a large number of microbial species, strict anaerobes and facultative anaerobic chemoheterotrophs, such as clostridia and enteric bacteria, are efficient producers of hydrogen. Despite having a higher evolution rate of hydrogen, the yield of hydrogen [mol H2 (mol substrate−1)] from fermentative processes is lower than that achieved using other methods; thus, the process is not economically viable in its present form. The pathways and experimental evidence cited in the literature reveal that a maximum of four mol of hydrogen can be obtained from substrates such as glucose. Modifications of the fermentation process, by redirection of metabolic pathways, gas sparging and maintaining a low partial pressure of hydrogen to make the reaction thermodynamically favorable, efficient product removal, optimum bioreactor design and integrating fermentative process with that of photosynthesis, are some of the ways that have been attempted to improve hydrogen productivity. This review briefly describes recent advances in these approaches towards improvement of hydrogen yield by fermentation.
Journal of Environmental Sciences-china, 2009
The conversion of glucose to hydrogen was evaluated using continuous stirred tank reactor at pH 5.5 with various hydraulic retention times (HRT) at 30°C. Furthermore, the population dynamics of hydrogen-producing bacteria was surveyed by fluorescence in-situ hybridization using probe Clost IV targeting the genus Clostridium based on 16S rRNA. It was clear that positive correlation was observed between the cells quantified with probe Clost IV and hydrogen yield of the respective sludge. The numbers of hydrogenproducing bacteria were decreased gradually with increasing HRT, were 9.2 × 10 8 , 8.2 × 10 8 , 2.8 × 10 8 , and 6.2 × 10 7 cell/mL at HRT 6, 8, 12, and 14 h, respectively. The hydrogen yield was 1.4-1.5 mol H 2 /mol glucose at the optimum HRT range 6-8 h. It is considered that the percentage of the hydrogen-producing bacteria to total bacteria is useful parameter for evaluation of hydrogen production process.
Comparison of hydrogen production by four representative hydrogen-producing bacteria
Journal of Industrial and Engineering Chemistry, 2008
The characteristics of hydrogen production by four different hydrogen-producing bacteria (Clostridium beijerinckii, Rhodobacter sphaeroides, anaerobic bacteria isolated from sludge digester and Bacillus megaterium) were investigated quantitatively. The mathematical analysis using Gompertz equation showed that C. beijerinckii was the best hydrogen producer from glucose in terms of hydrogen-production potential and specific hydrogen-production rate. However, the bacteria required relatively long lag time at high-initial glucose concentration. The anaerobic bacteria showing the highest maximum hydrogen-production rate and relatively short lag time have a limit of low-hydrogen-production potential because they are mixed culture and produce some amount of methane gas. C. beijerinckii will be used in the actual system for hydrogen production from carbohydrate but the anaerobic bacteria may be a good choice for the production of hydrogen from wastewater containing innumerable compounds.
Fermentative hydrogen production by microbial consortium
International Journal of …, 2008
Heat pre-treatment of the inoculum associated to the pH control was applied to select hydrogen-producing bacteria and endospores-forming bacteria. The source of inoculum to the heat pre-treatment was from a UASB reactor used in the slaughterhouse waste treatment. The molecular biology analyses indicated that the microbial consortium presented microorganisms affiliated with Enterobacter cloacae (97% and 98%), Clostridium sp. (98%) and Clostridium acetobutyricum (96%), recognized as H 2 and volatile acids' producers. The following assays were carried out in batch reactors in order to verify the efficiencies of sucrose conversion to H 2 by the microbial consortium: (1) 630.0 mg sucrose/L, (2) 1184.0 mg sucrose/L, (3) 1816.0 mg sucrose/L and (4) 4128.0 mg sucrose/L. The subsequent yields were obtained as follows: 15% (1.2 mol H 2 /mol sucrose), 20% (1.6 mol H 2 /mol sucrose), 15% (1.2 mol H 2 /mol sucrose) and 4% (0.3 mol H 2 /mol sucrose), respectively. The intermediary products were acetic acid, butyric acid, methanol and ethanol in all of the anaerobic reactors.
Icelandic Agricultural Sciences
The hydrogen production capacity of strain AK14, a moderate thermophilic bacterium was studied. According to 16S rRNA analysis the strain belongs to genus Clostridium but was most closely related to Anaerobacter polyendosporus (95.1% similarity). Growth for strain AK14 was observed at temperatures between 42 and 52°C with optimal growth at 50°C. Optimum pH for growth was at pH 6.5 but growth was observed from pH 4.5 to 7.5. Fermentation of glucose resulted in the production of acetate and butyrate (major) and ethanol (minor) as well as hydrogen and carbon dioxide. Effect of increased substrate (glucose) concentration was investigated and good correlation were observed between substrate loadings and end product formation up to 50 mM where clear inhibition was shown resulting in less glucose degraded and lower end product formation. The ability to utilize various carbon substrates were tested with positive growth observed on xylose, glucose, fructose, mannose, galactose, starch and xy...