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1.
V. A. Svetlichny T. G. Sokolova M. Gerhardt N. A. Kostrikina G. A. Zavarzin 《Microbial ecology》1991,21(1):1-10
A new group of extremely thermophilic, obligately anaerobic, carboxydotrophic eubacteria is described. The organisms are characterized
by a novel type of chemotrophic metabolism in thermophilic environments. They grow at temperatures up to 80–85°C chemolithotrophically
with 100% CO in the gas phase as the sole energy source. The CO oxidation is coupled to H2 and CO2 formation according to the equation CO+H2O → H2+CO2. No other products of metabolism are produced. The group of CO-utilizing, H2-producing anaerobes includes diverse bacteria. They are non-sporeforming rods differing in morphology, CO uptake rates, habitats,
and maximum growth temperatures. The new carboxydotrophic thermophilic anaerobes are widely distributed in freshwater and
coastal marine hydrotherms of the Kuril Islands.
Offprint requests to: V. A. Svetlichny. 相似文献
2.
Apart from being applied as an energy carrier, hydrogen is in increasing demand as a commodity. Currently, the majority of hydrogen (H2) is produced from fossil fuels, but from an environmental perspective, sustainable H2 production should be considered. One of the possible ways of hydrogen production is through fermentation, in particular, at elevated temperature, i.e. thermophilic biohydrogen production. This short review recapitulates the current status in thermophilic biohydrogen production through fermentation of commercially viable substrates produced from readily available renewable resources, such as agricultural residues. The route to commercially viable biohydrogen production is a multidisciplinary enterprise. Microbiological studies have pointed out certain desirable physiological characteristics in H2-producing microorganisms. More process-oriented research has identified best applicable reactor types and cultivation conditions. Techno-economic and life cycle analyses have identified key process bottlenecks with respect to economic feasibility and its environmental impact. The review has further identified current limitations and gaps in the knowledge, and also deliberates directions for future research and development of thermophilic biohydrogen production. 相似文献
3.
Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium thermosaccharolyticum and Thermoanaerobacterium aciditolerans could generate a high hydrogen production rate of 5600 mL H2/day/L, corresponding to a yield of 132 mL H2/g volatile solid (VS). The effluent from the hydrogen reactor was further converted to methane in the second reactor with the optimal production rate of 3380 mL CH4/day/L, corresponding to a yield of 239 mL CH4/g VS. Aceticlastic Methanosarcina mazei was the dominant methanogen in the methanogenesis stage. This work demonstrates that biohydrogen production can be very efficiently coupled with a subsequent step of methane production using desugared molasses. Furthermore, the mixed gas with a volumetric content of 16.5% H2, 38.7% CO2, and 44.8% CH4, containing approximately 15% energy by hydrogen is viable to be bio‐hythane. 相似文献
4.
H2-producing bacteria were isolated from anaerobic granular sludge. Out of 72 colonies (36 grown under aerobic conditions and
36 under anaerobic conditions) arbitrarily chosen from the agar plate cultures of a suspended sludge, 34 colonies (15 under
aerobic conditions and 19 under anaerobic conditions) produced H2 under anaerobic conditions. Based on various biochemical tests and microscopic observations, they were classified into 13
groups and tentatively identified as follows: From aerobic isolates,Aeromonas spp. (7 strains),Pseudomonas spp. (3 strains), andVibrio spp. (5 strains); from anaerobic isolates,Actinomyces spp. (11 strains),Clostridium spp. (7 strains), andPorphyromonas sp. When glucose was used as the carbon substrate, all isolates showed a similar cell density and a H2 production yield in the batch cultivations after 12h (2.24–2.74 OD at 600 nm and 1.02–1.22 mol H2/mol glucose, respectively). The major fermentation by-products were ethanol and acetate for the aerobic isolates, and ethanol,
acetate and propionate for the anaerobic isolates. This study demonstrated that several H2 producers in an anaerobic granular sludge exist in large proportions and their performance in terms of H2 production is quite similar. 相似文献
5.
Current status of the metabolic engineering of microorganisms for biohydrogen production 总被引:1,自引:0,他引:1
The improvement of H2 production capabilities of hydrogen (H2)-producing microorganisms is a challenging issue. Microorganisms have evolved for fast growth and substrate utilization rather than H2 production. To develop good H2-producing biocatalysts, many studies have focused on the redirection and/or reconstruction of cellular metabolisms. These studies included the elimination of enzymes and carbon pathways interfering or competing with H2 production, the incorporation of non-native metabolic pathways leading to H2 production, the utilization of various carbon substrates, the rectification of H2-producting enzymes (nitrogenase and hydrogenase) and photophosphorylation systems, and in silico pathway flux analysis, among others. Owing to these studies, significant improvements in the yield and rate of H2 production, and in the stability of H2 production activity, were reached. This review presents and discusses the recent developments in biohydrogen production, with a focus on metabolic pathway engineering. 相似文献
6.
Studies to examine the microbial fermentation of coal gasification products (CO2, H2 and CO) to methane have been done with a mixed culture of anaerobic bacteria selected from an anaerobic sewage digestor. The specific rate of methane production at 37°C reached 25 mmol/g cell hr. The stoichiometry for methane production was 4 mmol H2/mol CO2. Cell recycle was used to increase the cell concentration from 2.5 to 8.3 g/liter; the volumetric rate of methane production ran from 1.3 to 4 liter/liter hr. The biogasification was also examined at elevated pressure (450 psi) and temperature to facilitate interfacing with a coal gasifier. At 60°C, the specific rate of methane production reached 50 mmol/g cell hr. Carbon monoxide utilization by the mixed culture of anaerobes and by a Rhodopseudomonas species was examined. Both cultures are able to carry out the shift conversion of CO and water to CO2 and hydrogen. 相似文献
7.
An Anaerobic Chemostat That Permits the Collection and Measurement of Fermentation Gases 总被引:8,自引:5,他引:3
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A chemostat was designed to allow anaerobic growth in the culture vessel in the absence of a continuous stream of O2-free gas. Produced gases were collected within the culture and collection vessels, and pressure build-up was prevented by allowing gases to expand into a collapsed football bladder. The culture overflow was collected in a flask, held at 0 C, that was emptied by applying a positive CO2 pressure to the system. Ruminococcus albus, a H2 and CO2-producing anaerobe, was used to test the operation of the apparatus. H2 production was measured by sampling the various gas spaces of known volume and measuring H2 concentration by gas chromatography. Measurement of accumulated fermentation gases and the effects of the accumulation on fermentations can be studied with the apparatus. 相似文献
8.
Joseph J. Heijnen Han Gardeniers Luuk A. M. van der Wielen Walter M. van Gulik 《Biotechnology progress》2010,26(1):293-300
Aerobic batch cultivations of Candida utilis were carried out in two micro bioreactors with a working volume of 100 μL operated in parallel. The dimensions of the micro bioreactors were similar as the wells in a 96‐well microtiter plate, to preserve compatibility with the current high‐throughput cultivation systems. Each micro bioreactor was equipped with an electrochemical sensor array for the online measurement of temperature, pH, dissolved oxygen, and viable biomass concentration. Furthermore, the CO2 production rate was obtained from the online measurement of cumulative CO2 production during the cultivation. The online data obtained by the sensor array and the CO2 production measurements appeared to be very reproducible for all batch cultivations performed and were highly comparable to measurement results obtained during a similar aerobic batch cultivation carried out in a conventional 4L bench‐scale bioreactor. Although the sensor chip certainly needs further improvement on some points, this work clearly shows the applicability of electrochemical sensor arrays for the monitoring of parallel micro‐scale fermentations, e.g. using the 96‐well microtiterplate format. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 相似文献
9.
Michiel van Leeuwen Joseph J. Heijnen Han Gardeniers Luuk A. M. van der Wielen Walter M. van Gulik 《Biotechnology progress》2009,25(3):892-897
We developed and applied a conductometric method for the quantitative online measurement of the carbon dioxide (CO2) production during batch cultivations of Candida utilis on a 100‐μL scale. The applied method for the CO2 measurement consisted of absorption of the produced CO2 from the exhaust gas of the microbioreactor in an alkali solution, of which the conductivity was measured on‐line. The measured conductivity change of the alkali solution showed a linear relation with the total amount of CO2 absorbed. After calibration of the CO2 measurement system, it was connected to a well of a 96‐well microtiter plate. The mixing in the well was achieved by a magnetic stirrer. Using online measurement of the CO2 production during the cultivation, we show reproducible exponential batch growth of C. utilis on a 100‐μL scale. The CO2 production measurements obtained from the microcultivation were compared with the CO2 production measurement in a 4‐L bioreactor equipped with a conventional off‐gas analyzer. The measurements showed that on‐line measurement of the CO2 production rate in microbioreactors can provide essential data for quantitative physiological studies and provide better understanding of microscale cultivations. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 相似文献
10.
Kyohei Baito Satomi Imai Makoto Matsushita Miku Otani Yu Sato Hiroyuki Kimura 《Microbial biotechnology》2015,8(5):837-845
In a deep aquifer associated with an accretionary prism, significant methane (CH4) is produced by a subterranean microbial community. Here, we developed bioreactors for producing CH4 and hydrogen (H2) using anaerobic groundwater collected from the deep aquifer. To generate CH4, the anaerobic groundwater amended with organic substrates was incubated in the bioreactor. At first, H2 was detected and accumulated in the gas phase of the bioreactor. After the H2 decreased, rapid CH4 production was observed. Phylogenetic analysis targeting 16S rRNA genes revealed that the H2-producing fermentative bacterium and hydrogenotrophic methanogen were predominant in the reactor. The results suggested that syntrophic biodegradation of organic substrates by the H2-producing fermentative bacterium and the hydrogenotrophic methanogen contributed to the CH4 production. For H2 production, the anaerobic groundwater, amended with organic substrates and an inhibitor of methanogens (2-bromoethanesulfonate), was incubated in a bioreactor. After incubation for 24 h, H2 was detected from the gas phase of the bioreactor and accumulated. Bacterial 16S rRNA gene analysis suggested the dominance of the H2-producing fermentative bacterium in the reactor. Our study demonstrated a simple and rapid CH4 and H2 production utilizing anaerobic groundwater containing an active subterranean microbial community. 相似文献
11.
B. A. Annous J.-S. Shieh G.-J. Shen M. K. Jain J. G. Zeikus 《Applied microbiology and biotechnology》1996,45(6):804-810
Exogenous H2/CO2 and glucose were consumed simultaneously by Butyribacterium methylotrophicum when grown under glucose-limited conditions. CO2 reduction to acetate was coupled to H2 consumption. The addition of either H2 or CO2 to glucose batch fermentation resulted in an increase in cell density, hydrogenase (H2-consuming and -producing) activities and fatty acid production by B. methylotrophicum as compared to when N2 was the feed gas. Hydrogenase activities appeared to be tightly regulated and were produced at higher rates during the exponential
phase when CO2 was the feed gas as compared to H2 or N2. The increase in H2-consuming activity and decrease in H2-producing activity was correlated with an increase in butyrate synthesis. H2-consuming and ferredoxin (Fd)–NAD reductase activities increased while H2-producing and NADH–Fd reductase activities decreased in cells grown at pH 5.5 compared to those at pH 7.0. The molar ratio
of butyrate/acetate was shifted from 0.35 at pH 7.0 to 1.22 at pH 5.5. The addition of exogenous H2 did not decrease the butyrate/acetate ratio at pH 7.0 nor at pH 5.5. The results indicated that growth pH values regulated
both hydrogenase and Fd–NAD oxidoreductase activities such that, at acid pH, more intermediary electron flow was directed
towards butyrate synthesis than H2 production.
Received: 22 August 1995/Received revision: 18 December 1995/Accepted: 22 January 1996 相似文献
12.
Trophic links between fermentation and methanogenesis of soil derived from a methane‐emitting, moderately acidic temperate fen (pH 4.5) were investigated. Initial CO2:CH4 production ratios in anoxic microcosms indicated that methanogenesis was concomitant to other terminal anaerobic processes. Methane production in anoxic microcosms at in situ pH was stimulated by supplemental H2–CO2, formate or methanol; supplemental acetate did not stimulate methanogenesis. Supplemental H2–CO2, formate or methanol also stimulated the formation of acetate, indicating that the fen harbours moderately acid‐tolerant acetogens. Supplemental monosaccharides (glucose, N‐acetylglucosamine and xylose) stimulated the production of CO2, H2, acetate and other fermentation products when methanogenesis was inhibited with 2‐bromoethane sulfonate 20 mM. Glucose stimulated methanogenesis in the absence of BES. Upper soil depths yielded higher anaerobic activities and also higher numbers of cells. Detected archaeal 16S rRNA genes were indicative of H2–CO2‐ and formate‐consuming methanogens (Methanomicrobiaceae), obligate acetoclastic methanogens (Methanosaetaceae) and crenarchaeotes (groups I.1a, I.1c and I.3). Molecular analyses of partial sequences of 16S rRNA genes revealed the presence of Acidobacteria, Nitrospirales, Clamydiales, Clostridiales, Alpha‐, Gamma‐, Deltaproteobacteria and Cyanobacteria. These collective results suggest that this moderately acidic fen harbours phylogenetically diverse, moderately acid tolerant fermenters (both facultative aerobes and obligate anaerobes) that are trophically linked to methanogenesis. 相似文献
13.
14.
Hydrogen production by microalgae 总被引:9,自引:0,他引:9
John R. Benemann 《Journal of applied phycology》2000,12(3-5):291-300
The production of H2 gas from water and sunlightusing microalgae, `biophotolysis', has been a subjectof applied research since the early 1970s. A numberof approaches have been investigated, but most provedto have fundamental limitations or requireunpredictable research breakthroughs. Examples areprocesses based on nitrogen-fixing microalgae andthose producing H2 and O2 simultaneously fromwater (`direct biophotolysis'). The most plausibleprocesses for future applied R & D are those whichcouple separate stages of microalgal photosynthesisand fermentations (`indirect biophotolysis'). Theseinvolve fixation of CO2 into storagecarbohydrates followed by their conversion to H2by the reversible hydrogenase, both in dark andpossibly light-driven anaerobic metabolic processes. Based on a preliminary engineering and economicanalysis, biophotolysis processes must achieve closeto an overall 10% solar energy conversion efficiencyto be competitive with alternatives sources ofrenewable H2, such as photovoltaic-electrolysisprocesses. Such high solar conversion efficiencies inphotosynthetic CO2 fixation could be reached bygenetically reducing the number of light harvesting(antenna) chlorophylls and other pigments inmicroalgae. Similarly, greatly increased yields ofH2 from dark fermentation by microalgae could beobtained through application of the techniques ofmetabolic engineering. Another challenge is toscale-up biohydrogen processes with economicallyviable bioreactors.Solar energy driven microalgae processes forbiohydrogen production are potentially large-scale,but also involve long-term and economically high-riskR&D. In the nearer-term, it may be possible tocombine microalgal H2 production with wastewatertreatment. 相似文献
15.
Jose L. Sanz Nuria Rodriguez Cristina Escudero Daniel Carrizo Ricardo Amils 《Environmental microbiology》2021,23(7):3913-3922
Most of the terrestrial deep subsurfaces are oligotrophic environments in which some gases, mainly H2, CH4 and CO2, play an important role as energy and/or carbon sources. In this work, we assessed their biotic and abiotic origin in samples from subsurface hard-rock cores of the Iberian Pyrite Belt (IPB) at three different depths (414, 497 and 520 m). One set of samples was sterilized (abiotic control) and all samples were incubated under anaerobic conditions. Our results showed that H2, CH4 and CO2 remained low and constant in the sterilized controls while their levels were 4, 4.1 and 2.5 times higher respectively, in the unsterilized samples compared to the abiotic controls. The δ13CCH4-values measured in the samples (range −31.2 to −43.0 ‰) reveals carbon isotopic signatures that are within the range for biological methane production. Possible microorganisms responsible for the biotic production of the gases were assessed by CARD-FISH. The analysis of sequenced genomes of detected microorganisms within the subsurface of the IPB allowed to identify possible metabolic activities involved in H2 (Rhodoplanes, Shewanella and Desulfosporosinus), CH4 (Methanobacteriales) and CO2 production. The obtained results suggest that part of the H2, CH4 and CO2 detected in the deep subsurface has a biological origin. 相似文献
16.
Microalgal biomass has been a focus in the sustainable energy field, especially biodiesel production. The purpose of this
study was to assess the feasibility of treating microalgal biomass and cellulose by anaerobic digestion for H2 production. A microbial consortium, TC60, known to degrade cellulose and other plant polymers, was enriched on a mixture
of cellulose and green microalgal biomass of Dunaliella tertiolecta, a marine species, or Chlorella vulgaris, a freshwater species. After five enrichment steps at 60°C, hydrogen yields increased at least 10% under all conditions.
Anaerobic digestion of D. tertiolecta and cellulose by TC60 produced 7.7 mmol H2/g volatile solids (VS) which were higher than the levels (2.9–4.2 mmol/g VS) obtained with cellulose and C. vulgaris biomass. Both microalgal slurries contained satellite prokaryotes. The C. vulgaris slurry, without TC60 inoculation, generated H2 levels on par with that of TC60 on cellulose alone. The biomass-fed anaerobic digestion resulted in large shifts in short
chain fatty acid concentrations and increased ammonium levels. Growth and H2 production increased when TC60 was grown on a combination of D. tertiolecta and cellulose due to nutrients released from algal cells via lysis. The results indicated that satellite heterotrophs from
C. vulgaris produced H2 but the Chlorella biomass was not substantially degraded by TC60. To date, this is the first study to examine H2 production by anaerobic digestion of microalgal biomass. The results indicate that H2 production is feasible but higher yields could be achieved by optimization of the bioprocess conditions including biomass
pretreatment. 相似文献
17.
P. F. Levy G. W. Barnard D. V. Garcia-Martinez J. E. Sanderson D. L. Wise 《Biotechnology and bioengineering》1981,23(10):2293-2306
The gases CO, CO2, and H2 were used as substrates in anaerobic fermentations producing organic acids. Various mixed bacterial sources were used, including sewage sludge digester effluent, rabbit feces, and soil. Nonsterile microorganism selection was carried out using CO2/H2 and CO/H2 as the primary carbon and energy sources. Cultures were grown in specially designed, high-pressure (to 70 psig) flasks. Methanogenic bacteria were eliminated from the cultures. Liquid products of the fermentations were acetic through caproic acids, with the even-numbered acids predominating. Carbon balances showed conclusively that acetic acid was formed from carbon contained in the CO or CO2 feed gas. Measurements made included rates of acid product formation, cell density, and degree of gas utilization. Limited characterization of the microorganisms was also performed. Production of organic acids by mixed culture inocula from CO2/H2 or CO/H2 had not been reported previously. Application of this work is to the production of organic chemicals from synthesis gas (SNG), produced by the gasification of fossil fuels (peat, lignite, and various ranks of coals), biomass (agricultural and forest residues, and various biomass crops grown expressly for energy recovery), and municipal solid waste. 相似文献
18.
In the presence of active hydrogenophilic sulfate-reducing bacteria, the homoacetogenic bacterium Sporomusa acidovorans did not produce acetate during methanol degradation. H2S and presumably CO2 were the only end products. Since the sulfate-reducer did not degrade methnol or acetate, the sulfidogenesis from methanol was related to a complete interspecific hydrogen transfer between both species.In coculture with hydrogenophilic methanogenic bacteria (Methanobacterium formicicum, Methanospirillum hungatei), the interspecific hydrogen transfer with S. acidovorans was incomplete. Beside CH4 and presumably CO2, acetate was produced. The results suggested that H2-production and H2-consumption were involved during anaerobic methanol degradation by S. acidovorans and the hydrogenophilic anaerobes play an important role during methanol degradation by homoacetogenic bacteria in anoxic environments. 相似文献
19.
Using sodium-dithionite as an oxygen scavenger, the influences of different light intensities and periods of anaerobic pre-incubation in the dark on H2-photoproductivity were studied with the green algaChlorella fusca. By measuring hydrogen production in the light using manometric and gas chromatographic methods the effectiveness of sodium dithionite in stabilizing photoproduction was established. For high rates of H2-photoproduction high light intensities up to 30,000 lux (580 W m-2) were necessary; these are comparable to those required for light saturation of oxygen photoproduction by this alga. AlthoughChlorella fusca produces H2 immediately after transition to anaerobic conditions, the optimum rate of H2 production was reached after a 5 h dark adaptation period only. The results obtained are discussed with respect to characteristics of H2-photoproduction by green algae: the initial burst kinetics, the light saturation, and the obligate period of anaerobic adaptation. It is concluded that H2-photoproduction byChlorella is an anaerobic photosynthetic process which occurs in the absence of CO2 and can be experimentally stabilized by exogenous oxygen scavengers.Abbreviations DCMU
(3-(3,4-Dichlorophenyl)-1,1-dimethylurea)
- HEPES
(2-[4-(2-Hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) 相似文献
20.
Athanasios Lykidis Chia-Lung Chen Susannah G Tringe Alice C McHardy Alex Copeland Nikos C Kyrpides Philip Hugenholtz Hervé Macarie Alejandro Olmos Oscar Monroy Wen-Tso Liu 《The ISME journal》2011,5(1):122-130
Terephthalate (TA) is one of the top 50 chemicals produced worldwide. Its production results in a TA-containing wastewater that is treated by anaerobic processes through a poorly understood methanogenic syntrophy. Using metagenomics, we characterized the methanogenic consortium inside a hyper-mesophilic (that is, between mesophilic and thermophilic), TA-degrading bioreactor. We identified genes belonging to dominant Pelotomaculum species presumably involved in TA degradation through decarboxylation, dearomatization, and modified β-oxidation to H2/CO2 and acetate. These intermediates are converted to CH4/CO2 by three novel hyper-mesophilic methanogens. Additional secondary syntrophic interactions were predicted in Thermotogae, Syntrophus and candidate phyla OP5 and WWE1 populations. The OP5 encodes genes capable of anaerobic autotrophic butyrate production and Thermotogae, Syntrophus and WWE1 have the genetic potential to oxidize butyrate to CO2/H2 and acetate. These observations suggest that the TA-degrading consortium consists of additional syntrophic interactions beyond the standard H2-producing syntroph–methanogen partnership that may serve to improve community stability. 相似文献