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1.
Effects of Cycle Time on Properties of Aerobic Granules in Sequencing Batch Airlift Reactors 总被引:3,自引:0,他引:3
Fang Wang Feng-lin Yang Xing-wen Zhang Yi-hui Liu Han-min Zhang Jun Zhou 《World journal of microbiology & biotechnology》2005,21(8-9):1379-1384
Summary The granulation and properties of aerobic sludge were studied in two sequencing batch airlift reactors (SBARs). The synthetic
wastewater in the two reactors had initially different levels of COD (400 mg l−1 in R1 and 1600 mg l−1 in R2). A hydraulic cycle time of 3 and 12 h was conducted in the reactors R1 and R2, respectively and the process of granulation
was observed by optical microscopy. It was found that the course of granulation at a cycle time of 3 h in R1 was shorter than
that at cycle time of 12 h in R2 and the properties of aerobic granules were distinct in the reactors due to the different
hydraulic cycle time. Under a cycle time of 3 h, granule diameter was around 1.0–2.0 mm, VSS ratio was 92.08% with stronger
granule strength; under a cycle time of 12 h, granule diameter was around 0.5–1.0 mm, VSS ratio was 83.92% with weaker granule
strength. In addition, the morphology of microorganisms in granules was obviously dissimilar when the hydraulic cycle time
was different. It was concluded that the hydraulic cycle time plays a crucial role in the granulation and properties of aerobic
granules. It is expected that the experimental findings will provide useful information on factors affecting aerobic granulation. 相似文献
2.
Aerobic granules are dense and compact microbial aggregates with various bacterial species. Recently, aerobic granulation technology has been extensively explored for treatment of municipal and industrial wastewaters. However, little information is currently available with regard to their structure stability and integrity at levels of energy metabolism and cell communication. In the present study, a typical chemical uncoupler, 3,3′,4′,5-tetrachlorosalicylanilide with the power to dissipate proton motive force and subsequently inhibit adenosine triphosphate (ATP) generation, was used to investigate possible roles of ATP and cell communication in maintaining the structure stability and integrity of aerobic granules. It was found that inhibited ATP synthesis resulted in the reduced production of autoinducer-2 and N-acylhomoserine lactones essential for cell communication, while lowered extracellular polymeric substance (EPS) production was also observed. As a consequence, aerobic granules appeared to break up. This study showed that ATP-dependent quorum sensing and EPS were essential for sustaining the structure stability and integrity of aerobic granules. 相似文献
3.
Costanzo G Pino S Botta G Saladino R Di Mauro E 《Origins of life and evolution of the biosphere》2011,41(6):559-562
Nucleic bases are obtained by heating formamide in the presence of various catalysts. Formamide chemistry also allows the
formation of acyclonucleosides and the phosphorylation of nucleosides in every possible position, also affording 2′,3′ and
3′,5′ cyclic forms. We have reported that 3′,5′ cyclic GMP and 3′,5′ cyclic AMP polymerize in abiotic conditions yielding
short oligonucleotides. The characterization of this reaction is being pursued, several of its parameters have been determined
and experimental caveats are reported. The yield of non-enzymatic polymerization of cyclic purine nucleotides is very low.
Polymerization is strongly enhanced by the presence of base-complementary RNA sequences. 相似文献
4.
He-Long Jiang Abdul Majid Maszenan Zhi-Wei Zhao Joo-Hwa Tay 《Journal of industrial microbiology & biotechnology》2010,37(3):253-262
The physical structure and activity of aerobic granules, and the succession of bacterial community within aerobic granules
under constant operational conditions and shock loading were investigated in one sequencing batch reactor over ten months.
While the maturation phase of the granulation process began on day 30, the structure of microbial community changed markedly
until after three months of reactor operation under constant conditions with a loading rate of 1.5 g phenol L−1 day−1. A shock loading of 6.0 g phenol L−1 day−1 from days 182–192 led to divergence of bacterial community, an inhibition of the biomass activity, and a decrease in phenol
removal rate in the reactor. However, phenol was still completely removed under this disturbance. After the shock loading,
the mean sizes of aerobic granules increased, and the activity of the microbial population within the granules decreased,
although there appeared highly resilient for the dominant bacterial community of aerobic granules which mainly included β-Proteobacteria.
Correlation analysis suggested that biomass concentration and biomass loading were significantly related to the community
composition of aerobic granules during the whole operational period. The development of a relatively stable bacterial community
in aerobic granules implied that those distinct dominant microbes in aerobic granules were favorably selected and proliferated
under the operational conditions. 相似文献
5.
Sunday Adekunle Adebusoye Matthew O. Ilori Flynn W. Picardal Olukayode O. Amund 《World journal of microbiology & biotechnology》2008,24(1):61-68
Substantial metabolism of 2,3,4,5-tetrachlorobiphenyl (2,3,4,5-tetraCB) and 2,3′,4′,5-tetraCB by axenic cultures of Ralstonia sp. SA-5 and Pseudomonas sp. SA-6 was observed in the presence of biphenyl supplementation, although, the strains were unable to utilize tetrachlorobiphenyls
as growth substrate. The former was more amenable to aerobic degradation (∼70% degradation) than the latter (22–45% degradation).
Recovery of 2,5-chlorobenzoic acid and chloride from 2,3′,4′,5-tetraCB assay is an indication of initial dioxygenase attack
on the 3,4-dichlorophenyl ring. The PCB-degradative ability of both strains was also investigated by GC analysis of individual
congeners in Aroclor 1242 (100 ppm) following 12-day incubation with washed benzoate-grown cells. Results revealed two different
catabolic properties. Whereas strain SA-6 required biphenyl as inducer of the degradation activity, such induction was not
required by strain SA-5. Nearly all the detectable congeners in the mixture were extensively degraded (% reduction in ECD
area counts for individual congeners ranged from 50.0 to 100% and 14.2 to 100%, respectively, for SA-5 and SA-6). The two
strains exhibited no noticeable specificity for congeners with varying numbers of chlorine substitution and positions. The
degradative competence of these isolates most especially SA-5 makes them among the most versatile PCB-metabolizing organisms
yet reported. 相似文献
6.
Two sequencing batch reactors were synchronously operated to investigate the effect of manganese (II) (Mn2+) augmentation on aerobic granulation. Reactor 1 (R1) was added with 10 mg/L Mn2+, while there was no Mn2+ augmentation in reactor 2 (R2). Results showed that R1 had a faster granulation process than R2 and R1 performed better in
chemical oxygen demand (COD) and ammonium nitrogen (NH4+–N) removal efficiencies. Moreover, the mature granules augmented with Mn2+ behaved better on their physical characteristics and size distributions, and they also had higher production of extracellular
polymeric substances (EPS) content. The result of three-dimensional excitation and emission matrix fluorescence showed that
Mn2+ had the function of causing organic material diversity (especially proteins diversity) in EPS fraction from granules. Polymerase
chain reaction and denaturing gradient gel electrophoresis techniques were employed to analyze the microbial and genetic characteristics
in mature granules. The results exhibited that Mn2+ augmentation was mainly responsible for the higher microbial diversity of granules from R1 compared with that from R2. Uncultured
sludge bacterium A16 (AF234726) and Rhodococcus sp. WTZ-R2 (HM004214) were the major species in R1, while only uncultured sludge bacterium A16 (AF234726) in R2. Moreover,
there were eight species of organisms found in both two aerobic granules, and three species were found only in aerobic granules
from R1. It could be concluded that Mn2+ could enhance the sludge granulation process and have a key effect role on the biological properties during the sludge granulation. 相似文献
7.
Changes in structure,activity and metabolism of aerobic granules as a microbial response to high phenol loading 总被引:13,自引:0,他引:13
Four column-type sequential aerobic sludge blanket reactors were fed with phenol as the sole carbon and energy source and operated at loading rates of 1.0, 1.5, 2.0 and 2.5 kg phenol m–3 day–1. The results indicated that phenol loading exerted a profound influence on the structure, activity and metabolism of the aerobic granules. Compact granules with good settling ability were maintained at loadings up to 2.0 kg phenol m–3 day–1, and structurally weakened granules with enhanced production of extracellular polymers and proteins and significantly lower hydrophobicities were observed at the highest loading of 2.5 kg phenol m–3 day–1. Specific oxygen uptake rate, catechol 2,3-dioxygenase (C23O) and catechol 1,2-dioxygenase (C12O) activities peaked at a loading of 2.0 kg phenol m–3 day–1, and declined thereafter. Granules degraded phenol completely in all four reactors, mainly through the meta cleavage pathway as C23O activities were significantly higher than C12O activities. At the highest loading applied, the anabolism and catabolism of microorganisms were regulated such that phenol degradation proceeded exclusively via the meta pathway, apparently to produce more energy for overstimulation of protein production against phenol toxicity. This work contributes to a better understanding of the ability of aerobic granules to handle high-strength industrial wastewaters containing chemicals that are normally inhibitory to microbial growth. 相似文献
8.
Mamdouh M. Ghorab Heba M. Abdel-Salam Marwa A. El-Sayad Mohammed M. Mekhel 《AAPS PharmSciTech》2004,5(4):63-68
The purpose of this research was to evaluate β-cyclodextrin (β-CD) as a vehicle, either singly or in blends with lactose (spray-dried
or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of β-CD was investigated. The
tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated
for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to
thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution
studies. The effect of β-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced
2-way crossover study. Phase-solubility studies indicated an AL-type diagram with inclusion complex of 1∶1 molar ratio. The powder blends and granules of all formulations showed satisfactory
flow properties, compressibility, and drug content. All tablet formations prepared by direct compression or wet granulation
showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of β-CD
in the formulations up to 30%. The mean pharmacokinetic parameters (Cmax, Ke, and area under the curve [AUC]0−∞) were significantly increased in presence of β-CD. These results suggest that β-CD would facilitate the preparation of meloxicam
tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between
tablets prepared by direct compression and those prepared by wet granulation. Also, β-CD is particularly useful for improving
the oral bioavailablity of meloxicam. 相似文献
9.
Kinetic analysis on the two-step processes of AOB and NOB in aerobic nitrifying granules 总被引:1,自引:0,他引:1
Fang Fang Bing-Jie Ni Xiao-Yan Li Guo-Ping Sheng Han-Qing Yu 《Applied microbiology and biotechnology》2009,83(6):1159-1169
Complete granulation of nitrifying sludge was achieved in a sequencing batch reactor. For the granular sludge, batch experiments
were conducted to characterize the kinetic features of ammonia oxidizers (AOB) and nitrite oxidizers (NOB) in the granules
using the respirometric method. A two-step nitrification model was established to determine the kinetic parameters of both
AOB and NOB. In addition to nitrification reactions, the new model also took into account biomass maintenance and mass transfer
through the granules. The yield coefficient, maximum specific growth rate, and affinity constant for ammonium for AOB were
0.21 g chemical oxygen demand (COD) g−1 N, 0.09 h−1, and 9.1 mg N L−1, respectively, whereas the corresponding values for NOB were 0.05 g COD g−1 N, 0.11 h−1, and 4.85 mg N L−1, respectively. The model developed in this study performed well in simulating the oxygen uptake rate and nitrogen conversion
kinetics and in predicting the oxygen consumption of the AOB and NOB in aerobic granules. 相似文献
10.
Essential roles of eDNA and AI-2 in aerobic granulation in sequencing batch reactors operated at different settling times 总被引:1,自引:0,他引:1
Settling time has been considered as one of the most effective selection pressures for aerobic granulation in sequencing batch
reactors (SBRs), i.e., poorly settleable bioparticles would be washed out from SBRs, and the heavy and good settling ones
would be retained at a shorter setting time. However, its biological implication remains unclear. This study investigated
the microbiological mechanisms of aerobic granulation at different settling times. It provided experimental evidence for the
first time showing that a shorter settling time could enhance release of extracellular DNA through cell lysis, which in turn
initiated microbial aggregation leading to increased biomass size and density, while AI-2-mediated quorum sensing was found
not to be involved in initial aggregation. It was further shown that the AI-2-mediated quorum sensing system was activated
to regulate the growth and maturation of aerobic granules when the biomass density reached a threshold of 1.025 g ml−1. It appears from this study that a short settling time of SBR would induce microbiological and physiological responses of
bacteria which are required at different stages of aerobic granulation and provide new insights into biological mechanisms
of settling time-triggered aerobic granulation. 相似文献
11.
Aerobic granulation is a promising technology for wastewater treatment, but problems regarding its formation and stability need to be solved. Divalent metal ions, especially Ca2+, Mg2+ and Mn2+, have been demonstrated to play an important role in the process of aerobic granulation. Here, we studied whether iron ions can affect aerobic granulation. Granular sludge formed without iron ion addition (<0.02 mg Fe2+ L?1) was fluffy and had a finger-type structure and filamentous out-growth. The addition of iron ions to concentrations of 1 and 10 mg Fe2+ L?1 repressed the finger-type structure and filamentous out-growth. The results show that chemical precipitation in the granules with iron ion addition was higher than that in the granules without ferrous addition. The amount of precipitates was higher inside the granules than outside. This study demonstrates that iron ions (Fe2+/Fe3+) increase the size and stability of aerobic granular sludge but do not affect the granulation time, which is the time that the first granular sludge is observed. The study shows that aerobic granular sludge technology can be confidently applied to actual wastewater containing a high concentration of iron compounds. 相似文献
12.
Growth on dichlorobiphenyls with chlorine substitution on each ring by bacteria isolated from contaminated African soils 总被引:4,自引:0,他引:4
Adebusoye SA Picardal FW Ilori MO Amund OO Fuqua C Grindle N 《Applied microbiology and biotechnology》2007,74(2):484-492
Until recently, it was generally believed that the presence of more than one chlorine substituent prevented chlorinated biphenyls
from serving as a sole source of carbon and energy for aerobic bacteria. In this study, we report the isolation of three aerobic
strains, identified as Enterobacter sp. SA-2, Ralstonia sp. SA-4, and Pseudomonas sp. SA-6 from Nigerian polluted soils, that were able to grow on a wide range of dichlorobiphenyls (diCBs). In addition to
growing on all monochlorobiphenyls (monoCBs), the strains were all able to utilize 2,2′-, 2,4′-, and 2,3-diCB as a sole source
of carbon and energy. With the exception of strain SA-2, growth was also sustainable on 3,3′-, and 3,5-diCB. Washed benzoate-grown
cells were typically able to degrade 68 to 100% of the diCB (100 ppm) within 188 h, concomitant with a cell number increase
of up to three orders-of-magnitude and elimination of varying amounts of chloride. In many cases, stoichiometric production
of a chlorobenzoate (CBA) as a product was observed. During growth on 2,2′-, and 2,4′-diCB, organisms exclusively attacked
an o-chlorinated ring resulting in the production of 2-CBA and 4-CBA, respectively. A gradual decline in the concentration of
the latter was observed, which suggested that the product was being degraded further. In the case of 2,3-diCB, the unsubstituted
ring was preferentially metabolized. Initial diCB degradation rates were greatest for 2,4′-diCB (11.2 ± 0.91 to 30.3 ± 7.8 nmol/min
per 109 cells) and lowest for 2,2′-diCB (0.37 ± 0.12 to 2.7 ± 1.2 nmol/min per 109 cells). 相似文献
13.
An isolated bacterium, Alcaligenes denitrificans ITRC-4, metabolizes 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) under both aerobic and anaerobic conditions. The
aerobic metabolism is inhibited by 38% and 47% in the presence of 1.0 g L−1 of sodium acetate and sodium succinate, respectively, but remains uninhibited in the presence of 1.0 g L−1 of glucose. Also, the metabolism is inhibited completely in the presence of biphenyl vapors, as well as 0.8 g L−1 of 2,2′-bipyridyl. Under anaerobic conditions, DDT is metabolized into 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD),
which is further enhanced by 50% in the presence of 1.0 g L−1 of glucose. Besides, the bacterium also metabolizes 4-chlorobenzoate, which is accompanied by the release of chloride ions.
Received: 13 March 2002 / Accepted: 8 April 2002 相似文献
14.
The effects of shear force on the formation, structure and metabolism of aerobic granules 总被引:50,自引:0,他引:50
The effect of shear force on aerobic granulation was studied in four column-type, sequential aerobic sludge blanket reactors. Hydrodynamic turbulence caused by upflow aeration served as the main shear force in the systems. Results showed that aerobic granulation was closely associated with the strength of shear force. Compact and regular aerobic granules were formed in the reactors with a superficial upflow air velocity higher than 1.2 cm s(-1). However, only typical bioflocs were observed in the reactor with a superficial upflow air velocity of 0.3 cm s(-1) during the whole experimental period. The characteristics of the aerobic granules in terms of settling ability, specific gravity, hydrophobicity, polysaccharide and protein content and specific oxygen utilization rate (SOUR) were examined. It was found that the shear force has a positive effect on the production of polysaccharide, SOUR, hydrophobicity of cell surface and specific gravity of granules. The hydrophobicity of granular sludge is much higher than that of bioflocs. Therefore, it appears that hydrophobicity could induce and further strengthen cell-cell interaction and might be the main force for the initiation of granulation. The shear-stimulated production of polysaccharides favors the formation of a stable granular structure. This research provides experimental evidence to show that shear force plays a crucial role in aerobic granulation and further influences the structure and metabolism of granules. 相似文献
15.
K. A. Billingsley S. M. Backus O. P. Ward 《Applied microbiology and biotechnology》1999,52(2):255-260
A variety of commercial surfactants were tested to determine their effect on polychlorinated biphenyl (PCB) transformation
by Pseudomonas LB400. Initial tests determined that most surfactants were fully or partially able to solubilize the PCB congeners 2,5,2′-chlorobiphenyl
(CBP), 2,4,2′,4′-CBP, 2,3,5,2′,5′-CBP and 2,4,5,2′,4′,5′-CBP, at concentrations above the surfactants' critical micelle concentration
(CMC). Surfactants were also found to have no negative effect on bacterial survival, as cell numbers were the same or higher
after incubation in the presence of surfactants than after incubation without surfactants. A comparison of the extent of biotransformation
of single PCB congeners by the bacterium revealed that, at surfactant concentrations above the CMC, the presence of an anionic
surfactant promoted while nonionic surfactants inhibited PCB transformation, compared to a control with no surfactant. The
rates of transformation of PCB congeners were also higher in the presence of the anionic surfactant compared to the control.
The inhibitory effects of a nonionic surfactant, Igepal CO-630 at a concentration above its CMC, on transformation of 2,4,5,2′,5′-CBP
could be eliminated by diluting the surfactant/PCB solution to a concentration close to the surfactant CMC.
Received: 26 October 1998 / Received revision: 5 March 1999 / Accepted: 14 March 1999 相似文献
16.
In the aerobic granular sludge reactor, the substrate loading is related to the size of the aerobic granules cultivated. This study investigated the influence of substrate surface loading on the growth and substrate-utilization kinetics of aerobic granules. Results showed that microbial surface growth rate and surface biodegradation rate are fairly related to the substrate surface loading by the Monod-type equation. In this study, both the theoretical maximum growth yield and the Pirt maintenance coefficient were determined. It was found that the estimated theoretical maximum growth yield of aerobic granules was as low as 0.2 g biomass g–1 chemical oxygen demand (COD) and 10–40% of input substrate-COD was consumed through the maintenance metabolism, while experimental results further showed that the unit oxygen uptake by aerobic granules was 0.68 g oxygen g–1 COD, which was much higher than that reported in activated sludge processes. Based on the growth yield and unit oxygen uptake determined, an oxidative assimilation equation of acetate-fed aerobic granules was derived; and this was confirmed by respirometric tests. In aerobic granular culture, about 74% of the input substrate-carbon was converted to carbon dioxide. The growth yield of aerobic granules was three times lower than that of activated sludge. It is likely that high carbon dioxide production is the main cause of the low growth yield of aerobic granules, indicating a possible energy uncoupling in aerobic granular culture. 相似文献
17.
Su-Il Kang Seo-Young Kang Robert A. Kanaly Eunjung Lee Yoongho Lim Hor-Gil Hur 《Archives of microbiology》2009,191(6):509-517
The hypolipidemic agent gemfibrozil (GEM), which has been studied for its metabolism in humans and animals, was investigated
to elucidate its primary metabolism by Cunninghamella elegans. The fungus produced ten metabolites (FM1–FM9 and FM6′) from the biotransformation of GEM. Based on LC/MS/MS and NMR analyses,
a major metabolite, FM7, was identified as 2′-hydroxymethyl GEM. FM6 was considered to be 5′-hydroxymethyl GEM, after comparison
of results LC/MS, LC/MS/MS, and UV absorption spectra to FM7. The combined concentration of FM6 and FM7 was found to increase
up to 0.83 mM by day 2, and then decreased gradually with incubation time, followed by a noticeable increase in the biotransformation
product, FM1, up to 0.86 mM by day 15. NMR analyses confirmed that FM1 was 2′,5′-dihydroxymethyl GEM. Further minor oxidations
of the aromatic ring and carboxylic acid intermediates were also detected. Based upon these findings, the major fungal metabolic
pathway for GEM is likely to occur via production of 2′,5′-dihydroxymethyl GEM from 2′-hydroxymethyl GEM. These relatively
rapid and diverse biotransformations of GEM by C. elegans suggest that depending upon conditions, it may also follow a similar biodegradation fate when released into the natural environment. 相似文献
18.
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
19.
Sunil S. Adav Duu-Jong Lee Juin-Yih Lai 《Applied microbiology and biotechnology》2010,85(5):1601-1610
Aerobic sludge granules are compact, strong microbial aggregates that have excellent settling ability and capability to efficiently
treat high-strength and toxic wastewaters. Aerobic granules disintegrate under high organic loading rates (OLR). This study
cultivated aerobic granules using acetate as the sole carbon and energy source in three identical sequencing batch reactors
operated under OLR of 9–21.3 kg chemical oxygen demand (COD) m−3 day−1. The cultivated granules removed 94–96% of fed COD at OLR up to 9–19.5 kg COD m−3 day−1, and disintegrated at OLR of 21.3 kg COD m−3 day−1. Most tested isolates did not grow in the medium at >3,000 mg COD l−1; additionally, these strains lost capability for auto-aggregation and protein or polysaccharide productivity. This critical
COD regime correlates strongly with the OLR range in which granules started disintegrating. Reduced protein quantity secreted
by isolates was associated with the noted poor granule integrity under high OLR. This work identified a potential cause of
biological nature for aerobic granules breakdown. 相似文献
20.
Toxic coplanar polychlorinated biphenyls (Co-PCBs) were used as substrates for a degradation experiment with white-rot fungus, Phlebia brevispora TMIC33929, which is capable of degrading polychlorinated dibenzo-p-dioxins. Eleven PCB congener mixtures (7 mono-ortho- and 4 non-ortho-PCBs) were added to the cultures of P. brevispora and monitored by high resolution gas chromatography and mass spectrometry (HRGC/HRMS). Five PCB congeners, 3,3′,4,4′-tetrachlorobiphenyl, 2,3,3′,4,4′-pentachlorobiphenyl, 2,3′,4,4′,5-pentachlorobiphenyl, 3,3′,4,4′,5-pentachlorobiphenyl, and 2,3′,4,4′,5,5′-hexachlorobiphenyl were degraded by P. brevispora. To investigate the fungal metabolism of PCB, each Co-PCB was treated separately by P. brevispora and the metabolites were analyzed by gas chromatography and mass spectrometry (GC/MS) and identified on the basis of the GC/MS comparison with the authentic compound. Meta-methoxylated metabolite was detected from the culture containing each compound. Additionally, para-dechlorinated and -methoxylated metabolite was also detected from the culture with 2,3,3′,4,4′-pentachlorobiphenyl, 2,3′,4,4′,5-pentachlorobiphenyl, and 2,3′,4,4′,5,5′-hexachlorobiphenyl, which are mono-ortho-PCBs. In this paper, we identified the congener specific degradation of coplanar PCBs by P. brevispora, and clearly proved for the first time by identifying the metabolites that the white-rot fungus, P. brevispora, transformed recalcitrant coplanar PCBs. 相似文献