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1.
E. Kostyál E.-L. Nurmiaho-Lassila J. A. Puhakka M. Salkinoja-Salonen 《Applied microbiology and biotechnology》1997,47(6):734-741
This study deals with combining the biologi cal removal of organic halogens with the removal of nitrogen from bleached kraft
pulp mill wastewater in fluidized-bed reactors under nitrifying and denitrifying conditions. Untreated and biotreated bleached
kraft pulp mill wastewaters had no detrimental effect on nitrification or denitrification. The nitrifying biofilm reactor,
pregrown on synthetic inorganic feed with ammonia, removed without a lag phase adsorbable organic halogens [7.2 mg Cl (g biomass
volatile solids)−1day−1] from bleached kraft pulp mill wastewater and selected chlorophenols from synthetic wastewater. Electron microscopical examination
of the biofilm showed that bacteria, morphologically similar to the nitrifying species Nitrosomonas or Nitrobacter, and Nitrosospira were dominant. The denitrifying fluidized-bed reactor, pregrown on nitrate and methanol, denitrified without a lag phase bleached
kraft pulp mill wastewater. Under denitrifying conditions, 35% of the total organic carbon content of untreated bleached kraft
pulp mill waste water was removed. The reducing power delivered by untreated bleached kraft pulp mill wastewater for denitrification
was 2 mmol electrons/mmol carbon mineralized. Dechlorination under denitrifying conditions was negligible.
Received: 21 November 1996 / Received revision: 27 January 1997 / Accepted: 1 February 1997 相似文献
2.
G. Zellner E. Feuerhake H. J. Jördening A. J. L. Macario E. Conway de Macario 《Applied microbiology and biotechnology》1995,43(3):566-571
A denitrifying bacterial biofilm population established on a polypropylene substratum of a fixed-film reactor was characterized
by microscopy, scanning electron microscopy and immunofluorescence after 120 days of operation. The reactor, operated at pH
7.0, 22°C, and −180 mV with synthetic wastewater containing methanol/nitrate, achieved a denitrification rate of 0.24 mol
NO-
3 l-1 day-1 with a removal efficiency for nitrate of 95%–99% at an organic loading rate of 0.325 mol methanol l-1 day-1. The gas produced contained 2%–3% (v/v) methane and 3%–4% (v/v) carbon dioxide in addition to nitrogen. The biofilm contained
mainly cells of Methanobrevibacter arboriphilus antigenically related to strain DC, short, flagellated, gram-negatively staining rods of Pseudomonas sp. antigenically related to Pseudomonas stutzeri strain AN11, non-identified pink-pigmented rods and small lemon-shaped cells with mono- and bipolar appendages resembling
prosthecate Hyphomicrobium sp. The biofilm analysis provided evidence for a syntrophy between the denitrifying, methylotrophic, bacterial consortium
and hydrogenotrophic methanogens, which were identified by antigenic fingerprinting with 17 antibody probes.
Received: 11 July 1994/Received revision: 23 September 1994/Accepted: 28 September 1994 相似文献
3.
It is critical that an inexpensive electron- donor/carbon-source be found for selenium bioremedia-tion using the selenate-respiring
bacterium, Thauera selenatis. Since acetate is a preferred substrate for growth of this organism, a method was developed for fermenting the lactose in
whey to large amounts of acetate. Indigenous whey microorganisms fermented the whey lactose in this manner when grown in continuous
culture at a very slow dilution rate (D = 0.05 h−1). The successful use of the fermented whey lactose as the carbon-source/electron-donor feed for a laboratory-scale selenium-bioremediation
reactor system, inoculated with T. selenatis, treating selenium-contaminated drainage water was also demonstrated. Selenium oxyanions and nitrate were reduced by 98%.
Received: 30 October 1998 / Received revision: 26 January 1999 / Accepted: 5 February 1999 相似文献
4.
Complete degradation of tetrachloroethene by combining anaerobic dechlorinating and aerobic methanotrophic enrichment cultures 总被引:3,自引:0,他引:3
J. Gerritse V. Renard J. C. Gottschal J. Visser 《Applied microbiology and biotechnology》1995,43(5):920-928
Degradation of tetrachloroethene (perchloroethylene, PCE) was investigated by combining the metabolic abilities of anaerobic
bacteria, capable of reductive dechlorination of PCE, with those of aerobic methanotrophic bacteria, capable of co-metabolic
degradation of the less-chlorinated ethenes formed by reductive dechlorination of PCE. Anaerobic communities reductively dechlorinating
PCE, trichloroethene (TCE) and dichloroethenes were enriched from various sources. The maximum rates of dechlorination observed
for various chloroethenes in these batch enrichments were: PCE to TCE (341 μmol l-1 day-1), TCE to cis-dichloroethene (159 μmol l-1 day-1), cis-dichloroethene to chloroethene (99 μmol l-1 day-1) and trans-dichloroethene to chloroethene (22 μmol l-1 day-1). A mixture of these enrichments was inoculated into an anoxic fixed-bed upflow column. In this column PCE was converted
mainly into cis-1, 2-dichloroethene, small amounts of TCE and chloroethene, and chloride. Enrichments of aerobic methanotrophic bacteria
were grown in an oxic fixed-bed downflow column. Less-chlorinated ethenes, formed in the anoxic column, were further metabolized
in this oxic methanotrophic column. On the basis of analysis of chloride production and the disappearance of chlorinated ethenes
it was demonstrated that complete degradation of PCE was possible by combining these two columns. Operation of the two-column
system under various process conditions indicated that the sensitivity of the methanotrophic bacteria to chlorinated intermediates
represented the bottle-neck in the sequential anoxic/oxic degradation process of PCE.
Received: 24 October 1994 / Received revision: 20 January 1995 / Accepted: 23 January 1995 相似文献
5.
Freeze-dried, alginate-based beads, used for the immobilization of a denitrifying bacterium (Pseudomonas sp.), were filled with different concentrations (10%, 20%, 30% and 40%, w/w) of granular starch. The beads were incubated
under denitrifying conditions in laboratory-scale, flow-through columns and monitored for changes in their physical and denitrifying
properties. Freeze-dried beads containing high concentrations of starch were found to have better mechanical and denitrifying
properties than beads containing low concentrations of this filler. Nitrate removal by the beads was found to be correlated
with their starch content. Nitrite accumulation, as a result of incomplete denitrification, increased with the decrease in
starch content of the beads. Nitrite in the outlet of the columns was measured in all types of beads during the initial phase
of incubation but was undetectable, with the exception of beads with the lowest starch content, at later stages of incubation.
Received: 9 November 1998 / Received revision: 3 February 1999 / Accepted: 5 February 1999 相似文献
6.
Nitrate reduction by Citrobacter diversus under aerobic environment 总被引:17,自引:0,他引:17
A new aerobic denitrifier, Citrobacter diversus, was isolated from both nitrification and denitrification sludge. To monitor the variation in the concentration of nitrogen
oxides, aerobic denitrification by C. diversus was carried out in a batch reactor. When the nitrate concentration was greater than 180 mg N l−1, the nitrate reduction rate became stable. The effect of the C/N ratio on the denitrification activity was also investigated.
The results showed that the optimum denitrification activity was obtained when the C/N ratio was 4–5. The range of the C/N
ratio was higher than that for traditional anoxic denitrification. The effect of the dissolved oxygen concentration was further
studied; and it was found that the range of dissolved oxygen concentrations, both for specific growth rates and for specific
denitrification rates, was 2–6 mg−1. From these results, it can be concluded that both the concentration of dissolved oxygen and the C/N ratio are key factors
in the aerobic denitrification by C. diversus.
Received: 23 November 1999 / Received revision: 4 February 2000 / Accepted: 13 February 2000 相似文献
7.
Zheng Y Yang W Sun X Wang SP Rui YC Luo CY Guo LD 《Applied microbiology and biotechnology》2012,93(5):2193-2203
Knowledge about methanotrophs and their activities is important to understand the microbial mediation of the greenhouse gas
CH4 under climate change and human activities in terrestrial ecosystems. The effects of simulated warming and sheep grazing on
methanotrophic abundance, community composition, and activity were studied in an alpine meadow soil on the Tibetan Plateau.
There was high abundance of methanotrophs (1.2–3.4 × 108
pmoA gene copies per gram of dry weight soil) assessed by real-time PCR, and warming significantly increased the abundance regardless
of grazing. A total of 64 methanotrophic operational taxonomic units (OTUs) were obtained from 1,439 clone sequences, of these
OTUs; 63 OTUs (98.4%) belonged to type I methanotrophs, and only one OTU was Methylocystis of type II methanotrophs. The methanotroph community composition and diversity were not apparently affected by the treatments.
Warming and grazing significantly enhanced the potential CH4 oxidation activity. There were significantly negative correlations between methanotrophic abundance and soil moisture and
between methanotrophic abundance and NH4–N content. The study suggests that type I methanotrophs, as the dominance, may play a key role in CH4 oxidation, and the alpine meadow has great potential to consume more CH4 under future warmer and grazing conditions on the Tibetan Plateau. 相似文献
8.
Kallistova AY Kevbrina MV Nekrasova VK Shnyrev NA Einola JK Kulomaa MS Rintala JA Nozhevnikova AN 《Microbial ecology》2007,54(4):637-645
The enumeration of methanotrophic bacteria in the cover soil of an aged municipal landfill was carried out using (1) fluorescent
in situ hybridization (FISH) with horseradish peroxidase-labeled oligonucleotide probes and tyramide signal amplification, also known
as catalyzed reporter deposition-FISH (CARD-FISH), and (2) most probable number (MPN) method. The number of methanotrophs
was determined in cover soil samples collected during April–November 2003 from a point with low CH4 emission. The number of types I and II methanotrophs obtained by CARD-FISH varied from 15 ± 2 to 56 ± 7 × 108 cells g−1 absolute dry mass (adm) of soil and methanotrophs of type I dominated over type II. The average number of methanotrophs throughout
the cover soil profile was highest during May–September when the cover soil temperature was above 13°C. Methanotrophs accounted
for about 50% of the total bacterial population in the deepest cover soil layer owing to higher availability of substrate
(CH4). A lower number of methanotrophs (7 × 102 to 17 × 105 cells g−1 adm of soil) was determined by the MPN method compared to the CARD-FISH counts, thus confirming previous results that the
MPN method is limited to the estimation of the culturable species that can be grown under the incubation conditions used.
The number of culturable methanotrophs correlated with the methane-oxidizing activity measured in laboratory assays. In comparison
to the incubation-based measurements, the number of methanotrophs determined by CARD-FISH better reflected the actual characteristics
of the environment, such as release and uptake of CH4, temperature, and moisture, and availability of substrates. 相似文献
9.
Levente Bodrossy E. M. Holmes A. J. Holmes Kornél L. Kovács J. C. Murrell 《Archives of microbiology》1997,168(6):493-503
Two methanotrophic bacteria with optimum growth temperatures above 40° C were isolated. Thermotolerant strain LK6 was isolated
from agricultural soil, and the moderately thermophilic strain OR2 was isolated from the effluent of an underground hot spring.
When compared to the described thermophilic methanotrophs Methylococcus capsulatus and Methylococcus thermophilus, these strains are phenotypically similar to Methylococcus thermophilus. However, their 16S rRNA gene sequences are markedly different from the sequence of Methylococcus thermophilus (∼ 8% divergence) and, together with Methylomonas gracilis, they form a distinct, new genus within the γ-subgroup of the Proteobacteria related to extant Type I methanotrophs. Further
phenotypic characterisation showed that the isolates possess particulate methane monooxygenase (pMMO) but do not contain soluble
methane monooxygenase. The nucleotide sequence of a gene encoding pMMO (pmoA) was determined for both isolates and for Methylomonas gracilis. PmoA sequence comparisons confirmed the monophyletic nature of this newly recognised group of thermophilic methanotrophs
and their relationship to previously described Type I methanotrophs. We propose that strains OR2 and LK6, together with the
misclassified thermophilic strains Methylomonas gracilis VKM-14LT and Methylococcus thermophilus IMV-B3122, comprise a new genus of thermophilic methanotrophs, Methylocaldum gen. nov., containing three new species: Methylocaldum szegediense, Methylocaldum tepidum and Methylocaldum gracile.
Received: 2 April 1997 / Accepted: 23 July 1997 相似文献
10.
P. Arvidsson K. Nilsson H. Håkanson B. Mattiasson 《Applied microbiology and biotechnology》1998,49(6):677-681
A chemiluminescence detector was used to measure the production of nitric oxide, NO, from the denitrifying bacteria Pseudomonas stutzeri. NO is an intermediate when P. stutzeri converts nitrate into nitrogen gas. The reaction between NO and ozone is selective and sensitive in generating chemiluminescence.
Calibrations were made down to 1 nM, with a signal-to-noise ratio of 3. Bacteria were immobilised in alginate beads. Denitrification
experiments were made in an anaerobic non-growth medium by adding nitrate to a certain concentration in the reactor. The bacteria
were exposed to nitrate in the concentration range 1 pM–5 mM. The lowest concentration to give a measurable NO response was
100 nM.
Received: 16 October 1997 / Received revision: 20 January 1998 / Accepted: 24 January 1998 相似文献
11.
Denitrifiers associated with methanotrophs and their potential impact on the nitrogen cycle 总被引:1,自引:0,他引:1
Here I describe how losses of fixed nitrogen can occur in riparian zones by the activity of denitrifying bacteria associated with methane-oxidizing (methanotrophic) bacteria. Several methanotrophs catalyze nitrogen cycle processes that can occur in riparian buffer zones, including nitrification and nitrogen fixation. Methanotrophs can produce nitric and nitrous oxides during oxidation of ammonium (nitrification), but they cannot carry out denitrification. However, there is good evidence that denitrifying bacteria can be associated with methanotrophs and can use simple carbon compounds released by the methanotrophs as substrates for the denitrification reactions and for growth. Evidence is presented that denitrifiers isolated from methanotrophic gel-stabilized oxygen gradient systems can use methanol, formaldehyde, and formate, all methane oxidation intermediates, to support their denitrification. Such denitrification associated with methanotrophs can release dinitrogen and so contributes to losses of fixed nitrogen, and may also produce the important atmospheric trace gases nitric and nitrous oxides. Data presented also show that some methanotrophs produce nitrogen oxides, including nitrite, nitric oxide, and nitrous oxide, during growth on nitrate. Assimilatory reduction of nitrate appears to be a requirement for the release of these products. 相似文献
12.
M. B. Cassidy K. W. Shaw H. Lee J. T. Trevors 《Applied microbiology and biotechnology》1997,47(2):108-113
A pentachlorophenol(PCP)-degrading Pseudomonas sp. strain UG30 was encapsulated in κ-carrageenan for use in PCP degradation. Free and encapsulated cells were compared for
their ability to dechlorinate and mineralize 100–800 μg/ml sodium pentachlorophenate in broth. Dechlorination was measured
with a chloride ion electrode, and mineralization was measured by 14CO2 evolution from radiolabelled [U-14C]PCP. Free and encapsulated Pseudomonas sp. UG30 cells mineralized up to 200 μg/ml and 600 μg/ml PCP, respectively, after 21 days. Encapsulation of UG30 cells provided
a protective effect, allowing dechlorination and mineralization of high levels of PCP to occur.
Received: 3 May 1996 / Received revision: 4 September 1996 / Accepted: 13 September 1996 相似文献
13.
A. De Smul J. Dries L. Goethals H. Grootaerd W. Verstraete 《Applied microbiology and biotechnology》1997,48(3):297-303
In a mesophilic (30–35 °C), sulphidogenic, ethanol-fed expanded-granular-sludge-blanket reactor, sulphate, at loading rates
of up to 10.0–12.0 g Sl−1␣day−1, was removed with an average efficiency of more than 80%. The pH was between 7.7 and 8.3 and the maximal total dissolved
sulphide concentration was up to 20 mM S (650 mg S/l). The alkaline pH was maintained by either a pH-control unit with sodium
hydroxide or by stripping part of the sulphide and CO2 from the recycle with nitrogen gas. The superficial upstream liquid velocity (v
up) was 3.0–4.5 m/h. The ratio of ethanol to sulphur was near stoichiometry. At alkaline pH, the activity of the acetotrophic
sulphate-reducing bacteria, growing on acetate, was strongly enhanced, whereas at pH below 7.7 the acetotrophic sulphate-reducing
bacteria were inhibited by aqueous H2S. With regard to the removal efficiency and operational stability, external stripping with N2 and pH control were equally successful.
Received: 2 December 1996 / Received revision: 13 March 1997 / Accepted: 15 March 1997 相似文献
14.
Nitrifying granules cultivation in a sequencing batch reactor at a low organics-to-total nitrogen ratio in wastewater 总被引:4,自引:0,他引:4
It is possible to cultivate aerobic granular sludge at a low organic loading rate and organics-to-total nitrogen (COD/N) ratio
in wastewater in the reactor with typical geometry (height/diameter = 2.1, superficial air velocity = 6 mm/s). The noted nitrification
efficiency was very high (99%). At the highest applied ammonia load (0.3 ± 0.002 mg NH4+–N g total suspended solids (TSS)−1 day−1, COD/N = 1), the dominating oxidized form of nitrogen was nitrite. Despite a constant aeration in the reactor, denitrification
occurred in the structure of granules. Applied molecular techniques allowed the changes in the ammonia-oxidizing bacteria
(AOB) community in granular sludge to be tracked. The major factor influencing AOB number and species composition was ammonia
load. At the ammonia load of 0.3 ± 0.002 mg NH4+–N g TSS−1 day−1, a highly diverse AOB community covering bacteria belonging to both the Nitrosospira and Nitrosomonas genera accounted for ca. 40% of the total bacteria in the biomass. 相似文献
15.
Effect of dissolved oxygen and carbon–nitrogen loads on denitrification by an aerobic consortium 总被引:10,自引:0,他引:10
Patureau D Bernet N Delgenès JP Moletta R 《Applied microbiology and biotechnology》2000,54(4):535-542
Four samples of natural ecosystems and one sample from an activated sludge treatment plant were mixed together and progressively
adapted to alternating aerobic/anoxic phases in the presence of nitrate in order to enrich the microflora in aerobic denitrifiers.
Aerobic denitrifying performances of this mixed ecosystem at various dissolved oxygen concentrations and various carbon–nitrogen
loads were evaluated and compared to those obtained with the aerobic denitrifier Microvirgula aerodenitrificans. The consortium and the pure strain exhibited an aerobic denitrifying activity at air saturation conditions (7 mg dissolved
oxygen l–1), i.e. there was co-respiration of the two electron acceptors with significant specific nitrate reduction rates. Dissolved
oxygen concentrations had no influence on denitrifying performances above a defined threshold: 0.35 mg l–1 for the consortium and 4.5 mg l–1 for M. aerodenitrificans respectively. Under these thresholds, decreasing the dissolved oxygen concentrations enhanced the denitrifying activity of
each culture. The higher the carbon and nitrogen loads, the higher the performance of the aerobic denitrifying ecosystem.
However, for M. aerodenitrificans, the nitrate reduction percentage was affected more by variations in nitrogen load than in carbon load.
Received: 6 December 1999 / Received revision: 8 March 2000 / Accepted: 10 March 2000 相似文献
16.
Thermophilic acidification of dairy wastewater 总被引:2,自引:0,他引:2
Acidification of simulated dairy wastewater was conducted in an upflow reactor at 55 °C. Results showed that the degree of
acidification decreased with the increase in chemical oxygen demand (COD) loading rate, from 60.8% at 4 g l−1 day−1 to 27.1% at 24 g l−1 day−1. Carbohydrate was readily degraded at all loading rates, but degradation of protein and lipid decreased with the increase
in loading rate. Most carbohydrate degradation occurred at the reactor bottom, whereas protein was degraded mainly after the
carbohydrate became depleted. The predominant acidification products were acetate, propionate, butyrate and ethanol, whereas
formate, i-butyrate, valerate, i-valerate, caproate, lactate, methanol, propanol and butanol were present in lesser quantities. The increase in loading rate
resulted in the increase of propionate and the decrease of acetate, but had little effect on ethanol and butyrate productions.
Only 2.5–8.8% of influent COD was converted to hydrogen and methane. The biomass yield was 0.30–0.43 mg VSS mg−1 COD.
Received: 8 December 1999 / Received revision: 14 February 2000 / Accepted: 25 February 2000 相似文献
17.
Bioremediation of atrazine-contaminated soil by repeated applications of atrazine-degrading bacteria 总被引:5,自引:0,他引:5
Bioaugmentation has previously been unreliable for the in situ clean-up of contaminated soils because of problems with poor
survival and the rapid decline in activity of the bacterial inoculum. In an attempt to solve these problems, a 500-l batch
fermenter was investigated for its ability to deliver inoculum repeatedly to contaminated soils via irrigation lines. In a
field experiment, mesocosms were filled with 350 kg soil containing 100 mg kg−1 atrazine, and inoculated one, four or eight times with an atrazine-degrading bacterial consortium that was produced in the
fermenter. After 12 weeks, no significant degradation of atrazine had occurred in soil that was inoculated only once; whereas,
mesocosms inoculated four and eight times mineralized 38% and 72% of the atrazine respectively. Similar results were obtained
in a laboratory experiment using soil contaminated with 100 mg kg−1 [14C]atrazine. After 35 days, soil that was inoculated once with 108 cfu ml−1 of the consortium or with the atrazine-degrading bacterium, Pseudomonas sp. strain ADP, mineralized 17% and 35% of the atrazine respectively. In comparison, microcosms inoculated every 3 days with
the consortium or with Pseudomonas sp. (ADP) mineralized 64% or 90% of the atrazine over this same period. Results of these experiments suggest that repeated
inoculation from an automated fermenter may provide a strategy for bioaugmentation of contaminated soil with xenobiotic-degrading
bacteria.
Received: 20 November 1998 / Received revision: 8 February 1999 / Accepted: 12 February 1999 相似文献
18.
Characterization and optimization of a two-phase partitioning bioreactor for the biodegradation of phenol 总被引:2,自引:0,他引:2
An electrochemical reactor employing activated carbon fibers (ACF) was constructed for the disinfection of bacteria in drinking
water. The application of an alternating potential of 1.0 V and −0.8 V versus a saturated calomel electrode, for disinfecting
and desorbing bacteria, enabled reactor operation for 840 h. Drinking water was passed through the reactor in stop/flow mode:
300 ml/min flow for 12 h and no flow for 12 h, alternately. The bacterial cell density in treated water was always been less
than 20 cells/ml. It was also found that the formation of biofilm on the ACF reactor caused an increase in current, enabling
the self-detection of microbial fouling.
Received: 19 February 1996 / Received last revision: 23 July 1996 / Accepted: 2 September 1996 相似文献
19.
A. M. Fauzi David J. Hardman Alan T. Bull 《Applied microbiology and biotechnology》1996,46(5-6):660-666
The degradation of low concentrations of 1,3-dichloro-2-propanol (1,3-DCP) and related halohydrins by whole cells and cell-free
extracts of soil bacteria has been investigated. Three bacteria (strains A1, A2, A4), isolated from the same soil sample,
were distinguished on the basis of cell morphology, growth kinetics and haloalcohol dehalogenase profiles. Strain A1, probably
an Agrobacterium sp., dehalogenated 1,3-DCP with the highest specific activity (0.33 U mg protein−1) and also had the highest affinity for 1,3-DCP (K
m, 0.1 mM). Non-growing cells of this bacterium dehalogenated low concentrations of 1,3-DCP with a first-order rate constant
(k
1) of 1.13 h−1 . The presence of a non-dehalogenating bacterium, strain G1 (tentatively identified as Pseudomonas mesophilius), did not enhance the dehalogenation rate of low 1,3-DCP concentrations. However, the mixed-species consortium of strains
A1 and G1 had greater stability than the mono-species culture at DCP concentrations above 1.0 gl−1.
Received: 30 April 1996 / Received revision: 30 July 1996 / Accepted: 5 August 1996 相似文献
20.
Two plant-growth-promoting bacteria, Azospirillum brasilense Cd and Pseudomonas fluorescens 313, immobilized in 1983 in two types of alginate-bead inoculant (with and without skim-milk supplement) and later dried
and stored at ambient temperature for 14 years, were recovered in 1996. The population in each type of bead had decreased,
yet significant numbers survived (105–106 cfu/g beads). Population numbers depended on the bead type and the three independent bacterial counting methods: the conventional
plate-count method, indirect enzyme-linked immunosorbent assay and the limited-enrichment technique. Both bacterial species
retained several of their original physiological features. When inoculated onto wheat plants, both species colonized and produced
plant-growth effects equal to those of the contemporary strain from a culture collection or to their own 1983 records. This
study showed that bacteria can survive in alginate inoculant over long periods.
Received: 1 May 1998 / Received revision: 24 August 1998 / Accepted: 3 September 1998 相似文献