共查询到10条相似文献,搜索用时 109 毫秒
1.
A sequential anaerobic–aerobic biodegradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) was studied. The results demonstrated
that: (i) a complete degradation of RDX was achieved within 20 days using a consortium of bacteria from a wastewater activated
sludge, (ii) RDX degradation did not occur under aerobic conditions alone, (iii) RDX-degrading bacterial strain that was isolated
from the activated sludge completely degraded RDX within 2 days, and (iv) RDX- induced protein expressions were observed in
the RDX-degrading bacterial strain. Based on fatty acid composition and a confirmation with a 16S rRNA analysis, the RDX-degrading
bacterial strain was identified as a Bacillus pumilus—GC subgroup B. 相似文献
2.
Yeasts isolated from olive mill wastewaters from southern Italy: technological characterization and potential use for phenol removal 总被引:1,自引:0,他引:1
Milena Sinigaglia Nilde Di Benedetto Antonio Bevilacqua Maria Rosaria Corbo Angela Capece Patrizia Romano 《Applied microbiology and biotechnology》2010,87(6):2345-2354
Olive mill wastewater (OMW) samples from two traditional varieties (Peranzana and Ogliarola Garganica) of Apulian region (southern
Italy) and produced through continuous and traditional methods were microbiologically and chemically examined; thus, 104 yeasts
were isolated and selected for further analyses. The strains were identified as Candida boidinii, Pichia holstii, Pichia membranifaciens, and Saccharomyces cerevisiae and analyzed to assess their suitability to metabolize phenols. Based on phenol metabolism, 27 strains were selected and
inoculated into OMW aliquots to determine their ability to reduce phenols in vivo; then, five strains (identified with the
codes 682—C. boidinii and 625, 642, 647, and 941—P. holstii) were used as a cocktail in wastewaters for a final validation step. In this last experiment, the effects of the temperature
(10–30°C) and (NH4)2SO4 (0.0–6.0 g l−1) were studied through a central composite design approach, and the results highlighted that the cocktail was able to reduce
phenols by 40% at 10°C with 6.0 g l−1 of (NH4)2SO4 added. 相似文献
3.
Partial gyrB sequences (>1 kb) were obtained from 34 type strains of the genus Amycolatopsis. Phylogenetic trees were constructed to determine the effectiveness of using this gene to predict taxonomic relationships
within the genus. The use of gyrB sequence analysis as an alternative to DNA–DNA hybridization was also assessed for distinguishing closely related species.
The gyrB based phylogeny mostly confirmed the conventional 16S rRNA gene-based phylogeny and thus provides additional support for
certain of these 16S rRNA gene-based phylogenetic groupings. Although pairwise gyrB sequence similarity cannot be used to predict the DNA relatedness between type strains, the gyrB genetic distance can be used as a means to assess quickly whether an isolate is likely to represent a new species in the
genus Amycolatopsis. In particular a genetic distance of >0.02 between two Amycolatopsis strains (based on a 315 bp variable region of the gyrB gene) is proposed to provide a good indication that they belong to different species (and that polyphasic taxonomic characterization
of the unknown strain is worth undertaking).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
The GenBank accession numbers for the gyrB gene sequences obtained in this study are shown in Table 1. 相似文献
4.
An aerobic microorganism with an ability to utilize phenol as sole carbon and energy source was isolated from phenol-contaminated
wastewater samples. The isolate was identified as Bacillus amyloliquefaciens strain WJDB-1 based on morphological, physiological, and biochemical characteristics, and 16S rDNA sequence analysis. Strain
WJDB-1 immobilized in alginate–chitosan–alginate (ACA) microcapsules could degrade 200 mg/l phenol completely within 36 h.
The concentration of phenol was determined using differential pulse voltammetry (DPV) at glassy carbon electrode (GCE) with
a linear relationship between peak current and phenol concentration ranging from 2.0 to 20.0 mg/l. Cells immobilized in ACA
microcapsules were found to be superior to the free suspended ones in terms of improving the tolerance to the environmental
loadings. The optimal conditions to prepare microcapsules for achieving higher phenol degradation rate were investigated by
changing the concentrations of sodium alginate, calcium chloride, and chitosan. Furthermore, the efficiency of phenol degradation
was optimized by adjusting various processing parameters, such as the number of microcapsules, pH value, temperature, and
the initial concentration of phenol. This microorganism has the potential for the efficient treatment of organic pollutants
in wastewater. 相似文献
5.
Single-culture aerobic granules with <Emphasis Type="Italic">Acinetobacter calcoaceticus</Emphasis> 总被引:1,自引:0,他引:1
Aerobic granules are cultivated by a single bacterial strain, Acinetobacter calcoaceticus, in a sequencing batch reactor (SBR). This strain presents as a good phenol reducer and an efficient auto coagulator in the
presence of phenol, mediated by heat-sensitive adhesins proteins. Stable 2.3-mm granules were formed in the SBR following
a 7-week cultivation. These granules exhibit excellent settling attributes and degrade phenol efficiently at concentrations
of 250–2,000 mg l−1. The corresponding phenol degradation rate reached 993.6 mg phenol g−1 volatile suspended solids (VSS) day−1 at 250 mg l−1 phenol and 519.3 mg phenol g−1 VSS day−1 at 2,000 mg l−1 phenol concentration. Meanwhile, free A. calcoaceticus cells were fully inhibited at phenol >1,500 mg l−1. Denaturing gradient gel electrophoresis fingerprint profile demonstrated no genetic modification in the strain during aerobic
granulation. The present single-strain granules showed long-term structural stability and performed high phenol degrading
capacity and high phenol tolerance. The confocal laser scanning microscopic test revealed that live A. calcoaceticus cells principally distributed at 200–250 μm beneath the outer surface, with an extracellular polymeric substance layer covering
them to defend phenol toxicity. Autoaggregation assay tests demonstrated the possibly significant role of secreted proteins
on the formation of single-culture A. calcoaceticus granules. 相似文献
6.
High lipid concentration contained in wastewater inhibits the activity of microorganisms in biological wastewater treatment
systems such as activated sludge and methane fermentation. To reduce the inhibitory effects, microorganisms capable of efficiently
degrading edible oils were screened from various environmental sources. From Japanese soil, we isolated 2 bacteria strains
with high degradation abilities at an alkaline pH without consumption of biological oxygen demand (BOD) constituents. Acinetobacter sp. strain SS-192 and Pseudomonas aeruginosa strain SS-219 degraded 77.5 ± 0.6% and 89.5 ± 1.5%, respectively, of 3,000 ppm of mixed oil consisting of salad oil/lard/beef
tallow (1/1/1, w/w/w) at 37°C and pH 9.0 in 24 h. Efficient degradation by the two strains occurred at pH 8–9 and 25–40°C.
Strain SS-219 degraded lipids even at pH 3. The degradation rate of 3,000 ppm of salad oil, lard, and beef tallow by strain
SS-192 was 79.9 ± 2.6%, 63.6 ± 1.9%, and 70.1 ± 1.2%, respectively, during a 24-h cultivation. The degradation rate of 3,000 ppm
of salad oil, lard, and beef tallow by strain SS-219 was 82.3 ± 2.1%, 71.9 ± 2.2%, and 71.0 ± 1.1%, respectively, during a
24-h cultivation. After mixed oil degradation by both strains, the BOD value of the cell culture increased from 2,100 ppm
to 3,200–4,000 ppm. The fact that neither strain utilizes BOD ingredients will be beneficial to pretreatment of methane fermentation
systems such as upflow anaerobic sludge blanket reactors. In addition, the growth of usual heterotrophic microorganisms utilizing
soluble BOD can be suppressed under alkaline pH. 相似文献
7.
Isam A. Mohamed Ahmed Jiro Arima Tsuyoshi Ichiyanagi Emi Sakuno Nobuhiro Mori 《World journal of microbiology & biotechnology》2010,26(8):1455-1464
Soil isolates, identified as Pseudomonas sp. strain A9 and Pseudomonas sp. strain B9b (based on the phenotypic features and phylogenetic analysis) were found to degrade homocholine aerobically.
Morphological characterization using the optical microscope under light and phase contrast conditions showed that cells of
strain A9 formed short rods measuring approximately 0.5–1 × 1.5–2.0 μm in size while those of B9b formed long rods of 0.5–1 × 2.5–3.0 μm
during the early growth phase on both nutrient broth and basal-homocholine (basal-HC) media. Strain A9 was able to grow on
basal-HC medium at a wide range of temperatures (4–41°C) whereas strain B9b was not able to grow at either 4 or 41°C. Comparative
16S rRNA sequencing studies indicated that strain A9 fell into the Pseudomonas putida subclade whereas strain B9b located in Pseudomonas fulva subclade. Washed cells of strains A9 and B9b degraded homocholine completely within 6 h with concomitant formation of several
metabolites. Analysis of the metabolites by capillary electrophoresis, fast atom bombardment–mass spectrometry, and gas chromatography–mass
spectrometry, showed trimethylamine (TMA) as the major metabolite beside β-alanine betaine and trimethylaminopropionaldehyde.
Therefore, the possible degradation pathway of homocholine in the isolated strains is through successive oxidation of the
alcohol group (–OH) to aldehyde (–CHO) and acid (–COOH), and thereafter the cleavage of β-alanine betaine C–N bonds yielding
trimethylamine and an alkyl chain. 相似文献
8.
Ilmara Varotto Roma Neto Renan Augusto Ribeiro Mariangela Hungria 《World journal of microbiology & biotechnology》2010,26(7):1291-1302
Biodiversity of diazotrophic symbiotic bacteria in the tropics is a valuable but still poorly studied resource. The objective
of this study was to determine if a second housekeeping gene, glnII, in addition to the 16S rRNA, can be employed to improve the knowledge about taxonomy and phylogeny of rhizobia. Twenty-three
elite rhizobial strains, very effective in fixing nitrogen with twenty-one herbal and woody legumes (including species from
fourteen tribes in the three subfamilies of the family Leguminosae) were selected for this study; all strains are used as commercial inoculants in Brazil. Complete sequences of the 16S rRNA
and partial sequences (480 bp) of the glnII gene were obtained. The same primers and amplification conditions were successful for sequencing the glnII genes of bacteria belonging to five different rhizobial genera—Bradyrhizobium, Mesorhizobium, Methylobacterium, Rhizobium, Sinorhizobium)—positioned in distantly related branches. The analysis of the concatenated genes (16S rRNA + glnII) considerably improved information about phylogeny and taxonomy of rhizobia in comparison to the single analysis of the 16S
rRNA. Nine strains might belong to new species. The complementary analysis of the glnII gene was successful with all strains and improved the phylogenetic clustering and clarified the taxonomic position of several
strains. The strategy of including the analysis of glnII, in addition to the 16S rRNA, is cost- and time- effective for the characterization of large rhizobial culture collections
or in surveys of many isolates. 相似文献
9.
Duc Danh Ha 《Biodegradation》2018,29(5):499-510
Thauera sp. strain DKT isolated from sediment utilized 2,4-dichlorophenoxyacetic acid (2,4D) and its relative compounds as sole carbon and energy sources under anaerobic conditions and used nitrate as an electron acceptor. The determination of 2,4D utilization at different concentrations showed that the utilization curve fitted well with the Edward model with the maximum degradation rate as 0.017?±?0.002 mM/day. The supplementation of cosubstrates (glucose, acetate, sucrose, humate and succinate) increased the degradation rates of all tested chemical substrates in both liquid and sediment slurry media. Thauera sp. strain DKT transformed 2,4D to 2,4-dichlorophenol (2,4DCP) through reductive side-chain removal then dechlorinated 2,4DCP to 2-chlorophenol (2CP), 4-chlorophenol (4CP) and phenol before complete degradation. The relative degradation rates by the isolate in liquid media were: phenol?>?2,4DCP?>?2CP?>?4CP?>?2,4D?≈?3CP. DKT augmentation in sediment slurry enhanced the degradation rates of 2,4D and chlorophenols. The anaerobic degradation rates in the slurry were significantly slower compared to the rates in liquid media. 相似文献
10.
Tributyl phosphate (TBP) is an organophosphorous compound, used extensively (3000–5000 tonnes/annum) as a solvent for nuclear
fuel processing and as a base stock in the formulation of fire-resistant aircraft hydraulic fluids and other applications.
Because of its wide applications and relative stability in the natural environment TBP poses the problem of pollution and
health hazards. In the present study, fifteen potent bacterial strains capable of using tributyl phosphate (TBP) as sole carbon
and phosphorus source were isolated from enrichment cultures. These isolates were identified on the basis of biochemical and
morphological characteristics and 16S rRNA gene sequence analysis. Phylogenetic analysis of 16S rRNA gene sequences revealed
that two isolates belonged to class Bacilli and thirteen to β and γ-Proteobacteria. All these isolates were found to be members
of genera Alcaligenes, Providencia, Delftia, Ralstonia, and Bacillus. These isolates were able to tolerate and degrade up to 5 mM TBP, the highest concentration reported to date. The GC–MS method
was developed to monitor TBP degradation. Two strains, Providencia sp. BGW4 and Delftia sp. BGW1 showed respectively, 61.0 ± 2.8% and 57.0 ± 2.0% TBP degradation within 4 days. The degradation rate constants,
calculated by first order kinetic model were between 0.0024 and 0.0099 h−1. These bacterial strains are novel for TBP degradation and could be used as an important bioresource for efficient decontamination
of TBP polluted waste streams. 相似文献