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1.
Abstract Samples of water, sediment and bacterial mat from hot springs in Grændalur and Hveragerdi areas in southwestern Iceland were screened at 70°C and 80°C for thermophilic denitrifying bacteria by culturing in anaerobic media containing nitrate or N2 O as the terminal oxidant. The s springs ranged in temperature from 65–100°C and included both neutral (pH 7–8.5) and acidic (pH 2.5–4) types. Nitrate reducing bacteria (nitrate → nitrite) and denitrifiers (nitrate → N2 ) were found that grew at 70°C but not at 80°C in nutrient media at pH 8. Samples from neutral springs that were cultured at pH 8 failed to yield a chemolithotrophic, sulfur-oxidizing and nitrate-reducing bacterium, and samples from acidic springs that were cultured at pH 3.5 seemed entirely to lack dissimilatory, nitrate-utilizing bacteria. No sample yielded an organism capable of growth solely by N2 O respiration. The denitrifiers appeared to be Bacillus . Two such Bacillus strains were examined in pure culture and found to exhibit the unusual denitrification phenotype described previously for the mesophile, Pseudomonas aeruginosa , and one other strain of thermophilic Bacillus . The phenotype is characterized by the ability to grow by reduction of nitrate to N2 with N2 O as an intermediate but a virtual inability to reduce N2 O when N2 O was the sole oxidant. 相似文献
2.
Abstract Samples of water, sediment and bacterial mat from hot springs in Grændalur and Hveragerdi areas in southwestern Iceland were screened at 70°C and 80°C for thermophilic denitrifying bacteria by culturing in anaerobic media containing nitrate or N2 O as the terminal oxidant. The springs ranged in temperature from 65–100°C and included both neutral (pH 7–8.5) and acidic (pH 2.5–4) types. Nitrate reducing bacteria (nitrate → nitrite) and denitrifiers (nitrate → N2 ) were found that grew at 70°C but not at 80°C in nutrient media at pH 8. Samples from neutral springs that were cultured at pH 8 failed to yield a chemolithotrophic, sulfur-oxidizing and nitrate-reducing bacterium, and samples from acidic springs that were cultured at pH 3.5 seemed entirely to lack dissimilatory, nitrate-utilizing bacteria. No sample yielded an organism capable of growth solely by N2 O respiration. The denitrifiers appeared to be Bacillus . Two such Bacillus strains were examined in pure culture and found to exhibit the unusual denitrification phenotype described previously for the mesophile, Pseudomonas aeruginosa , and one other strain of thermophilic Bacillus . The phenotype is characterized by the ability to grow by reduction of nitrate to N2 with N2 O as an intermediate but a virtual inability to reduce N2 O when N2 O was the sole oxidant. 相似文献
3.
W.W. de Herder M.P. Hazenberg A.M. Pennock-Schröder G. Hennemann T.J. Visser 《FEMS microbiology letters》1986,35(2-3):249-253
Abstract 35 bacterial strains isolated from the human faecal flora were screened for hydrolysis of the glucuronides of 3,3',5-triiodothyronine and 3,3'-diiodothyronine. Two Gram-positive obligately anaerobic strains possessed glucuronidase activity. These strains probably belong to the genus Eubacterium , but ethanol was produced in high concentrations during glucose fermentation, which makes final classification difficult. Considering the number of bacteria in the intestinal flora (> 108 /ml) and the biliary excretion of iodothyronine conjugates, the strains must be able to hydrolyse a major part of the total daily intestinal supply of these iodothyronine metabolites. The study extends previous observations with faecal suspensions of human and rat origin [24]. The relevance of bacterial β-glucuronidase activity for a possible enterohepatic circulation of iodothyronines is discussed. 相似文献
4.
B. Ben Bohlool 《Archives of microbiology》1975,106(3):171-174
Several hot springs in the Rotorua-Taupo regions, North Island, New Zealand, were tested for the presence of extremely thermophilic acidophilic bacteria. In the majority of the springs, ranging in temperature from 43–96°C and in pH from 2.1–6.9, direct microscopic observations revealed the presence of both rod-shaped and spherical bacteria. Isolations were attempted at 70°C and pH 2.0 and 7.0, with either yeast extract for heterotrophic growth, or elemental sulfur as the sole source of energy for autotrophic growth. Eight of the samples produced grwoth at pH 2.0 with either yeast extract or sulfur, but none of the samples grew at pH 7.0. All the isolates obtained, resembled Sulfolobus acidocaldarius, a thermophilic acidophilic bacterium which has previously been reported from various regions in the Northern Hemisphere. Immunofluorescence examination of six of these isolates revealed varying degrees of cross reactions with two already characterized Sulfolobus isolates from the Yellowstone National Park, U.S.A. This paper is the first published record of Sulfolobus from the Southern Hemisphere. 相似文献
5.
A technique is described for studying hot spring microbial morphotypes by using electron microscope grids incubatedin situ. Such studies revealed the presence of filaments bearing swollen saclike structures in a number of New Zealand hot springs. There was considerable variation in the size, structure, and morphology of the filaments and the saclike structures. 相似文献
6.
Abstract Anaerobic thermophilic xylan-degrading bacteria present in unenriched and enriched 70°C samples from two Icelandic hot springs were enumerated at 68, 78, 90 and 99°C by the use of the Most-Probable-Number method. Xylan was used as substrate. From the samples taken at 70°C and incubated at the temperatures previously described no growth was observed above 78°C. A total of ten strains were isolated and characterized from the positive MPN enrichment cultures from the MPN experiments. A higher number of different strains could be isolated in the enriched samples compared with the unenriched, control samples from the same hot spring. Introduction of xylan, i.e., in situ enrichment, into one of the hot springs changed the bacterial population, as none of the bacteria isolated from the unenriched samples were isolated from the enriched samples. All the isolated bacteria were asporogenous, non-motile and gram-negative rods. One long thin rod had morphological similarities to members of the genus Dictyoglomus and was found in both hot spring samples. 相似文献
7.
《Critical reviews in biotechnology》2013,33(1):31-40
After introducing thermophilic anaerobic digestion (AD), characteristics of thermophilic methanogens are provided. Accordingly, (a) site of occurrence, (b) morphological characteristics (shape and motility), (c) biochemical characteristics (Gram character and % G+C profile), (d) nutritional characteristics (NaCl requirement and substrate specificity), and (e) growth characteristics (pH and temperature) of thermophilic methanogens are described. Some studies of the thermophilic AD are cited with their operational management problems. Subsequently, strategies to maximize net energy production are given, including mode of heating the bioreactors, role of agitation to promote AD performance and mode/intensity of mixing. Finally, advantages as well as drawbacks of AD under thermophilic conditions are given, concluding with its applications. 相似文献
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9.
Two proteolytic thermophilic aerobic bacterial strains, PA-9 and PA-5, were isolated from Buranga hot springs in western Uganda.
The cells were rods, approximately 10–12 μm in length and 3 μm in width. Isolate PA-9 grew at between 38°C and 68°C (optimum,
62°C), and PA-5 grew at between 37°C and 72°C (optimum, 60°C). Both isolates grew optimally at pH 7.5–8.5. Their 16S rRNA
gene sequences indicated that they belong to the newly described genus Geobacillus. Zymogram analysis of the crude enzyme extracts revealed the presence of two extracellular proteases for isolate PA-5, and
at least eight for isolate PA-9. The optimum temperature and pH for casein-degrading activity were 70°C, pH 6.5 for isolate
PA-9, but caseinolytic activity could also be observed at 2°C. In the case of isolate PA-5, optimal activity was observed
over a temperature and pH range of 50–70°C and pH 5–10, respectively.
Received: 26 November 2001 / Accepted: 12 December 2001 相似文献
10.
E. N. Kondratieva E. V. Zacharova V. I. Duda V. V. Krivenko 《Archives of microbiology》1989,151(2):117-122
A new anaerobic thermophilic Gram-positive, nonsporeforming bacterium strain ZE-1 was isolated from a hot spring of Kamchatka (USSR). The cells are rod-shaped, (0.5–0.8 · 2.0–20 m), non-motile. The bacterium can grow between 42 and 75°C; the optimal temperature is 65°C. The growth is possible between pH values 5.0 and 8.5; optimal pH is 7.0. The cultures grow on the media containing peptone, yeast extract, or casein hydrolysate as nitrogen sources in the presence of glucose or some other sugars, mannitol or starch. The main fermentation products of glucose are ethanol, acetate, lactate, H2, CO2; byproducts are propionic, butyric and isovaleric acids. Glucose is metabolized via Embden-Meyerhoff-Parnas pathway. Molecular hydrogen does not inhibit growth. The bacterium does not reduce aceton to isopropanol, but is able to form H2S from elemental sulfur. The bacterium contains a soluble hydrogenase. This enzyme catalyzes both evolution and uptake of H2 and is active in the presence of methyl viologen. The DNA-base composition is 34.6 mol%; the genome size 2.08x109 D. The name proposed for the isolated bacterium strain ZE-1 is Thermoanaerobium lactoethylicum spec. nov. 相似文献
11.
Thermophilic anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor 总被引:1,自引:0,他引:1
Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35 ± 2 °C) reactor as a control, thermophilic anaerobic digestion (55 ± 2 °C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m3 d) and HRT of 24 h; the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pretreatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW. 相似文献
12.
Dogan Karadag Annukka E. Mkinen Elena Efimova Jaakko A. Puhakka 《Bioresource technology》2009,100(23):5790-5795
Batch experiments were conducted to investigate the thermophilic biohydrogen production using an enrichment culture from a Turkish hot spring. Following the enrichment, the culture was heat treated at 100 °C for 10 min to select for spore-forming bacteria. H2 production was accompanied by production of acetate, butyrate, lactate and ethanol. H2 production was associated by acetate–butyrate type fermentation while accumulation of lactate and ethanol negatively affected the H2 yield. H2 production was highest in the temperature range from 49.6 to 54.8 °C and optimum values for initial pH and concentrations of iron, yeast extract and glucose were 6.5, 40 mg/l, 4–13.5 g/l, respectively. PCR–DGGE profiling showed that the heat treated culture consisted of species closely affiliated to genus Thermoanaerobacterium. 相似文献
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16.
Anna Derekova Rossica Mandeva Margarita Kambourova 《World journal of microbiology & biotechnology》2008,24(9):1697-1702
Phylogenetic diversity of culturable bacteria from genus Bacillus and related genera, isolated from 18 Bulgarian hot springs was investigated in association with their functional diversity.
Sixty-seven thermophilic and facultative thermophilic strains were isolated under aerobic conditions at 60°C. Sixty-six of
them belonged to eight species in four genera from Bacillus group: Anoxybacillus, Geobacillus, Brevibacillus and Bacillus. Representatives of the genus Anoxybacillus predominated. Based on phylogenetic analysis (<97% sequence similarity) four strains belonged to groups representing potentially
novel species. Producers of carbohydrases, degrading 12 from the tested 13 substrates were isolated. About half of the isolates
degraded amylose by exo- or endo-mechanism of action of their enzymes. The isolates degrading hemicellulose carbohydrates
like arabinan, arabinoxylan, β-glucan, galactan, galactomannan and xyloglucan were reached to. Some of the microorganisms
were able to uptake microbial polysaccharides like curdlan and gellan and their enzymes were between first reported thermostable
enzymes in their groups, like gellan lyase and curdlan lyase A relation between species affiliation and their functional activity
was observed—all A. gonensis strains were producer of amylolytic enzymes, most of Brevibacillus ruber strains were able to grow in a minimal medium with xanthan. 相似文献
17.
Jakob K. Kristjansson Arni Ingason Gudni A. Alfredsson 《Archives of microbiology》1985,140(4):321-325
Thermophilic obligately autotrophic hydrogen-oxidizing bacteria were isolated from several alkaline hot springs in Iceland. The bacteria were Gram negative rods, 0.4–0.5 m in diameter and 3–4 m long but 6–7 m long cells without septa were often seen. Long and short laments are formed. Spores, flagella or lipid granules were not observed. Strains H1 and H12 grew optimally at 70° C and pH 6.5 under mixture of air plus 0.6 atm H2 and 0.1 atm CO2. The cells contained cytochromes and carotenoid-like pigments. They would not grow on agar or silicia gel plates. The cells would not grow heterotrophically on organic substrates and were inhibited by most of these same organic compounds and agar in low concentrations. They were very sensitive to common antibiotics. The role of these bacteria in the hot spring ecosystem is discussed. 相似文献
18.
Thomas M. Wahlund Carl R. Woese Richard W. Castenholz Michael T. Madigan 《Archives of microbiology》1991,156(2):81-90
Thermophilic green sulfur bacteria of the genus Chlorobium were isolated from certain acidic high sulfide New Zealand hot springs. Cells were Gram-negative nonmotile rods of variable length and contained bacteriochlorophyll c and chlorosomes. Cultures of thermophilic chlorobia grew only under anaerobic, phototrophic conditions, either photoautotrophically or photoheterotrophically. The optimum growth temperature for the strains of thermophilic green sulfur bacteria isolated was 47–48°C with generation times of about 2 h being observed. The upper temperature limit for growth was about 52°C. Thiosulfate was a major electron donor for photoautotrophic growth while sulfide alone was only poorly used. N2 fixation was observed at 48°C and cell suspensions readily reduced acetylene to ethylene. The G+C content of DNA from strains of thermophilic chlorobia was 56.5–58.2 mol% and the organisms positioned phylogenetically within the green sulfur bacterial branch of the domain Bacteria. The new phototrophs are described as a new species of the genus Chlorobium, Chlorobium tepidum.This paper is dedicated to Professor Norbert Pfennig on the occasion of his 65th birthday 相似文献
19.
The thermophilic, anaerobic fermentation of hemicellulosic subtrates by Thermoanaerobacter strain B6A was investigated using a variety of commercially-available hemicelluloses which had been characterized by physical and chemical analysis. Products of hemicellulose fermentation included ethanol, acetic acid, lactic acid, H2, and CO2 in ratios which varied depending on the hemicellulose used. Both the rate and extent of substrate utilization (as estimated from product formation) varied in the order: unidentified mannan/xyloglucan > xylan > 4-O-methylglucuronoxylan > arabinoxylan > type II arabinogalactan=0. Rates of product formation were enhanced up to twofold by autoclaving of substrates,which partially depolymerized the substrates and in some cases altered their composition. Total extent of product formation, however, was similar in autoclaved and non-autoclaved substrates. Hemicellulose fermentations were mediated by one or more constitutive extracellular enzyme activities. Component monosaccharides of hemicelluloses in their natural isomeric configurations supported rapid growth (max = 0.3–1.0 h–1), while unnatural isomers were not utilized.The wide carbohydrate utilization spectrum of this strain apparently reflects its role as a versatile primary consumer in the hot spring bacterial-algal mat from which it was isolated.Abbreviations GC
Gas chromatography
- HPLC
High-performance liquid chromatography
- MS
Mass spectroscopy
- TLC
Thinlayer chromatography
- TMS
Trimethylsilyl
Contribution No. 3696 of the Central Research and Development Department 相似文献
20.
Putative anaerobic activity in aerated composts 总被引:5,自引:0,他引:5
C F Atkinson D D Jones J J Gauthier 《Journal of industrial microbiology & biotechnology》1996,16(3):182-188
It has been suggested that anaerobic microenvironments develop in aerobic composts, regardless of the aeration system used, and that anaerobic activity is responsible for odor generation and nitrogen losses. This study was designed to measure levels of microorganisms capable of anaerobic growth in two aerated composts: municipal solid waste, a relatively nutrient-rich compost, and pulp and paper-mill solid waste, which is relatively nutrient-poor. Anaerobic microorganisms were isolated from both composts at mesophilic and thermophilic temperatures. The majority of the anaerobic mesophiles were facultative anaerobes, whereas facultative, anaerobic thermophiles varied from 0 to 100%. Serially-diluted samples were spot-plated onto various media to preserve microbial consortia. Levels of aerobic and anaerobic exoenzyme production on spot-plates were similar on cell-wall, starch, and casein media. Although microbial levels on spread plates indicate that aerobes are present in much higher numbers than anaerobes (in 47 of 56 subsamples, 90% of the population were aerobes), microbial growth levels and exoenzyme production on spot-plates indicate that anaerobes may be responsible for a large portion (greater than or equal to 72%) of the metabolic activity in anaerobic microenvironments of aerobic composts. 相似文献