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1.
The effect of nonionic surfactants on the polycyclic aromatic hydrocarbon (PAH) oxidation rates by the extracellular ligninolytic enzyme system of the white-rot fungus Bjerkandera sp. strain BOS55 was investigated. Various surfactants increased the rate of anthracene, pyrene, and benzo[a]pyrene oxidation by two to fivefold. The stimulating effect of surfactants was found to be solely due to the increased bioavailability of PAH, indicating that the oxidation of PAH by the extracellular ligninolytic enzymes is limited by low compound bioavailability. The surfactants were shown to improve PAH dissolution rates by increasing their aqueous solubility and by decreasing the PAH precipitate particle size. The surfactant Tween 80 was mineralized by Bjerkandera sp. strain BOS55; as a result both the PAH solubilizing activity of Tween 80 and its stimulatory effect on anthracene and pyrene oxidation rates were lost within 24 h after addition to 6-day-old cultures. It was observed that the surfactant dispersed anthracene precipitates recrystallized into larger particles after Tween 80 was metabolized. However, benzo[a]pyrene precipitates remained dispersed, accounting for a prolonged enhancement of the benzo[a]pyrene oxidation rates. Because the endogenous production of H2O2 is also known to be rate limiting for PAH oxidation, the combined effect of adding surfactants and glucose oxidase was studied. The combined treatment resulted in anthracene and benzo[a]pyrene oxidation rates as high as 1450 and 450 mg L-1 d-1, respectively, by the extracellular fluid of 6-day-old fungal cultures. 相似文献
2.
Raw mixed-dye wastewater from a textile dye-producing plant was partly decolorized by the agaric white-rot fungus, Clitocybula dusenii. The fungus had higher Mn peroxidase (MnP) and laccase activities when grown with dye effluent than in control cultures. The activity of MnP increased commensurately with the proportion of the raw dye wastewater in the medium (control: 20 U l–1; 10% v/v effluent: 67 U l–1; 25% v/v effluent: 130 U l–1; and 33% v/v effluent: 180 U l–1). Maximal decolorization rates were achieved over 20 d at 28 °C using four-fold diluted dye-containing effluent on a 5 d pre-grown mycelium. 相似文献
3.
The ability of the white-rot fungus Phanerochaete chrysosporium (INA-12) to degrade various polynuclear aromatic hydrocarbons (PAH) was investigated. Under static, non-nitrogen-limiting conditions, P. chrysosporium mineralized both phenanthrene and benzo[a]pyrene. Total mineralization, based on radioactive tracing, was limited to 1.8%–3% for phenanthrene and benzo[a]pyrene respectively. In both cases the pattern of mineralization did not correlate temporally with the production of lignin peroxidase activity. Sorption of radiolabelled material to the biomass was very significant with 22% and 40% of the total radioactivity being sorbed for benzo[a]pyrene and phenanthrene respectively. A number of models were examined to predict the sorption isotherms, the best performance being obtained with a three-parameter empirical model. It is apparent that lignin peroxidase is not necessarily involved in the biodegradation of all PAH and that a significant factor in PAH biodegradation and/or disappearance in cultures with the intact fungus may be attributed to sorption phenomena. 相似文献
4.
M. J. J. Kotterman E. Heessels E. de Jong J. A. Field 《Applied microbiology and biotechnology》1994,42(1):179-186
A recently isolated white-rot strain, Bjerkandera sp. strain BOS55, displays high extracellular peroxidase activity, and rapidly degrades polycyclic aromatic hydrocarbons (PAH). In this study, the culture conditions for the biodegradation of the model PAH compound, anthracene, were optimized with respect to O2, N, and C. An additional objective was to determine if the decolorization of the polymeric ligninolytic indicator dye, Poly R-478, could be correlated to anthracene biodegradation observed under a wide range of culture conditions. The supply of O2 was found to be the most important parameter in the biodegradation of anthracene. Increasing culture aeration enhanced the biodegradation of anthracene and the accumulation of its peroxidase-mediated oxidation product anthraquinone. Decolorization of Poly R-478 was less affected by inadequate aeration. Provided that ample aeration was supplied, the degradation of anthracene under different culture conditions was strongly correlated with the ligninolytic activity as indicated by the rate of Poly R-478 decolorization. Concentrations up to 22 mM NH4
+ N did not repress anthracene biodegradation and only caused a 0%–40% repression of the Poly R-478 decolorizing activity in various experiments. A cosubstrate requirement of 100 mg glucose / mg anthracene biodegraded was observed in this study. 相似文献
5.
Out of a number of white-rot fungal cultures, strains ofIrpex lacteus andPleurotus ostreatus were selected for degradation of 7 three- and four-ring unsubstituted aromatic hydrocarbons (PAH) in two contaminated industrial
soils. Respective data for removal of PAH in the two industrial soils byI. lacteus were: fluorene (41 and 67%), phenanthrene (20 and 56%), anthracene (29 and 49%), fluoranthene (29 and 57%), pyrene (24 and
42%), chrysene (16 and 32%) and benzo[a]anthracene (13 and 20%). In the same two industrial soilsP. ostreatus degraded the PAH with respective removal figures of fluorene (26 and 35%), phenanthrene (0 and 20%), anthracene (19 and 53%),
fluoranthene (29 and 31%), pyrene (22 and 42%), chrysene (0 and 42%) and benzo[a]anthracene (0 and 13%). The degradation of PAH was determined against concentration of PAH in non-treated contaminated soils
after 14 weeks of incubation. The fungal degradation of PAH in soil was studied simultaneously with ecotoxicity evaluation
of fungal treated and non-treated contaminated soils. Compared to non-treated contaminated soil, fungus-treated soil samples
indicated decrease in inhibition of bioluminescence in luminescent bacteria (Vibrio fischerii) and increase in germinated mustard (Brassica alba) seeds.
An erratum to this article is available at . 相似文献
6.
Baldrian P in Der Wiesche C Gabriel J Nerud F Zadrazil F 《Applied and environmental microbiology》2000,66(6):2471-2478
The white-rot fungus Pleurotus ostreatus was able to degrade the polycyclic aromatic hydrocarbons (PAHs) benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, and benzo[ghi]perylene in nonsterile soil both in the presence and in the absence of cadmium and mercury. During 15 weeks of incubation, recovery of individual compounds was 16 to 69% in soil without additional metal. While soil microflora contributed mostly to degradation of pyrene (82%) and benzo[a]anthracene (41%), the fungus enhanced the disappearance of less-soluble polycyclic aromatic compounds containing five or six aromatic rings. Although the heavy metals in the soil affected the activity of ligninolytic enzymes produced by the fungus (laccase and Mn-dependent peroxidase), no decrease in PAH degradation was found in soil containing Cd or Hg at 10 to 100 ppm. In the presence of cadmium at 500 ppm in soil, degradation of PAHs by soil microflora was not affected whereas the contribution of fungus was negligible, probably due to the absence of Mn-dependent peroxidase activity. In the presence of Hg at 50 to 100 ppm or Cd at 100 to 500 ppm, the extent of soil colonization by the fungus was limited. 相似文献
7.
Influence of Cadmium and Mercury on Activities of Ligninolytic Enzymes and Degradation of Polycyclic Aromatic Hydrocarbons by Pleurotus ostreatus in Soil
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Petr Baldrian Carsten in der Wiesche Jií Gabriel Frantiek Nerud Frantiek Zadrail 《Applied microbiology》2000,66(6):2471-2478
The white-rot fungus Pleurotus ostreatus was able to degrade the polycyclic aromatic hydrocarbons (PAHs) benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, and benzo[ghi]perylene in nonsterile soil both in the presence and in the absence of cadmium and mercury. During 15 weeks of incubation, recovery of individual compounds was 16 to 69% in soil without additional metal. While soil microflora contributed mostly to degradation of pyrene (82%) and benzo[a]anthracene (41%), the fungus enhanced the disappearance of less-soluble polycyclic aromatic compounds containing five or six aromatic rings. Although the heavy metals in the soil affected the activity of ligninolytic enzymes produced by the fungus (laccase and Mn-dependent peroxidase), no decrease in PAH degradation was found in soil containing Cd or Hg at 10 to 100 ppm. In the presence of cadmium at 500 ppm in soil, degradation of PAHs by soil microflora was not affected whereas the contribution of fungus was negligible, probably due to the absence of Mn-dependent peroxidase activity. In the presence of Hg at 50 to 100 ppm or Cd at 100 to 500 ppm, the extent of soil colonization by the fungus was limited. 相似文献
8.
Soil samples from an agricultural field contaminated with 10 ppm14C-benz(a)anthracene in glass tubes were brought into contact with cultures of wood-rotting fungi, precultivated on wheat straw substrate.
Forty-five strains of white-rot fungi and four brown-rot fungi were tested for their ability to colonize the soil and to mineralize14C-benz(a)anthracene to14CO2 within a 20-week incubation time. Twenty-two white-rot fungi and all brown-rot fungi were unable to colonize the soil. Twenty-three
strains of white-rot fungi, all belonging to the genusPleurotus, colonized the soil. During the experiment the noncolonizing fungi and their substrate disintegrated more and more to a nonstructured
pulp from which water diffused into the soil. The same phenomenon was observed in the control which contained only straw without
fungus and contaminated soil. In samples with colonizing fungi the substrate as well as the mycelia in the soil remained visibly
unchanged during the entire experiment. Surprisingly, most samples with fungi not colonizing the soil and the control without
fungus liberated between 40 and 58 % of the applied radioactivity as14CO2 whereas the samples with the colonizing fungi respired only 15–25 % as14CO2. This was 3–5 times more14CO2 than that liberated from the control (4.9 %) which contained only contaminated soil without straw and fungus. A similar result
was obtained with selected colonizing and noncolonizing fungi and soil contaminated with 10 ppm14C-pyrene. However, in pure culture studies in which14C-pyrene was added to the straw substrate,Pleurotus sp. (P2), as a representative of the colonizing fungi, mineralized 40.3 % of the added radioactivity to14CO2. The noncolonizing fungiDichomitus squalens andFlammulina velutipes liberated only 17.2 or 1.7 %, respectively, as14CO2. These results lead to the hypothesis that the native soil microflora stimulated by the formed products of straw lysis is
responsible for high degradation rates found with noncolonizing fungi. 相似文献
9.
V. Renganathan S. N. Usha Flordeliz Lindenburg 《Applied microbiology and biotechnology》1990,32(5):609-613
Summary Cellulose-degrading cultures of the white-rot fungus Phanerochaete chrysosporium produce two extracellular cellobiose-oxidizing enzymes, cellobiose oxidase and cellobiose: quinone oxidoreductase. These two enzymes bind strongly to microcrystalline cellulose (MCC) in the pH range 4–7; above neutral pH their affinity for MCC decreases. Cellulose-bound enzymes could not be eluted with phosphate buffer (20 mM, pH 6) containing polyols (10%), KCl (1 M), urea (1 M) or 1% ionic or non-ionic detergent. TRIS or borate buffer at pH 9 eluted 30%–35% of the cellobiose-oxidizing enzyme activity. The cellulose-immobilized enzymes oxidized cellobiose actively, suggesting that the catalytic sites are not involved in cellulose binding. These results suggest that the cellobiose-oxidizing enzymes of P. chrysosporium may be organized into two domains: a cellulose-binding domain and a catalytic domain.Offprint requests to: V. Renganathan 相似文献
10.
The white-rot fungi Trametes versicolor PRL 572, Trametes versicolor MUCL 28407, Pleurotus ostreatus MUCL 29527, Pleurotus sajor-caju MUCL 29757 and Phanerochaete chrysosporium DSM 1556 were investigated for their ability to degrade the polycyclic aromatic hydrocarbons (PAH) anthracene, benz[a]anthracene and dibenz[a,h]anthracene in soil. The fungi were grown on wheat straw and mixed with artificially contaminated soil. The results of this
study show that, in a heterogeneous soil environment, the fungi have different abilities to degrade PAH, with Trametes showing little or no accumulation of dead-end metabolites and Phanerochaete and Pleurotus showing almost complete conversion of anthracene to 9,10-anthracenedione. In contrast to earlier studies, Phanerochaete showed the ability to degrade the accumulated 9,10-anthracenedione while Pleurotus did not. This proves that, in a heterogeneous soil system, the PAH degradation pattern for white-rot fungi can be quite different
from that in a controlled liquid system.
Received: 20 March 1996 / Received revision: 2 July 1996 / Accepted: 8 July 1996 相似文献
11.
Miren Zumárraga Francisco J. Plou Humberto García-Arellano Antonio Ballesteros 《Biocatalysis and Biotransformation》2013,31(2-4):219-228
Fungal laccases are useful for several remarkable transformations, such as bioremediation of polycyclic aromatic hydrocarbons (PAHs), synthesis of phenolic-based resins, oxidation of lignin derivatives and others. Most of these substrates are barely water-soluble, and although polar organic co-solvents may be added to enhance their solubility, transformation rates dramatically decrease due to the negative effect of organic solvents on the protein structure. Laccase from Myceliophthora thermophila variant T2 (MtLT2) has been submitted to laboratory evolution in Saccharomyces cerevisiae with the aim of improving activity and stability in organic co-solvents. Some 4500 clones created by random mutagenesis were screened in two rounds of directed evolution. Libraries were explored under increasing concentrations of acetonitrile and ethanol, and several mutants with improved features were purified and further characterised. Turnover rates of MtLT2 in 30% (v/v) acetonitrile and 50% (v/v) ethanol were increased up to 6.5- and 7.5-fold, respectively. The best variants showed similar rates in 20% (v/v) acetonitrile or 30% (v/v) ethanol as the parent type in aqueous media. Mutant laccases were also tested for the oxidation of anthracene in the presence of 20% (v/v) acetonitrile. 相似文献
12.
Nonexhaustive extraction (propanol, butanol, hydroxypropyl-β-cyclodextrin [HPCD]), persulfate oxidation and biodegradability assays were employed to determine the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soil. After 16 weeks incubation, greater than 89% of three-ring compounds (acenaphthene, anthracene, fluorene, and phenanthrene) and 21% to 79% of four-ring compounds (benz[a]anthracene, chrysene, fluoranthene, and pyrene) were degraded by the indigenous microorganisms under biopile conditions. No significant decrease in five- (benzo[a]pyrene, benzo[b+k]fluoranthene) and six-ring compounds (benz[g,h,i]perylene, indeno[1,2,3-c,d]pyrene) was observed. Desorption of PAHs using propanol or butanol could not predict PAH biodegradability: low-molecular-weight PAH biodegradability was underestimated whereas high-molecular-weight PAH biodegradability was overestimated. Persulfate oxidation and HPCD extraction of creosote-contaminated soil was able to predict three- and four-ring PAH biodegradability; however, the biodegradability of five-ring PAHs was overestimated. These results demonstrate that persulfate oxidation and HPCD extraction are good predictors of PAH biodegradability for compounds with octanol-water partitioning coefficients of < 6. 相似文献
13.
Seo HB Kim HJ Lee OK Ha JH Lee HY Jung KH 《Journal of industrial microbiology & biotechnology》2009,36(2):285-292
A method for measuring the ethanol concentration in a yeast culture broth was developed using both microtubes and a 96-deepwell
microplate. The strategy involved first the solvent extraction of ethanol from the yeast culture broth and measurements of
the ethanol concentration using the dichromate oxidation method. Particular focus was made on selecting the extraction solvent
as well as determining the measurable range of ethanol concentrations using this solvent extraction-dichromate oxidation method.
This method was developed as an assay format in 2.0-ml microtubes and 1.2-ml 96-deepwell microplates, and the ethanol concentration
in the batch cultures and fed-batch fermentations was measured. Tri-n-butyl phosphate [non-alcoholic solvent, density = 0.9727, solubility in water = 0.028% (w/v)] was used for solvent extraction
when measuring the ethanol concentration from the yeast culture broth. The maximum detectable ethanol concentration was 8%
(v/v) when 10 g potassium dichromate in 100 ml of 5 M sulfuric acid was used. The concentrations determined from the solvent
extraction-dichromate oxidation methods were remarkably similar to those of gas chromatography in which samples were prepared
from seven experiments, such as four batch cultures and three fed-batch fermentations. 相似文献
14.
M. Wolter F. Zadrazil R. Martens M. Bahadir 《Applied microbiology and biotechnology》1997,48(3):398-404
The degradation of eight unlabeled highly condensed polycyclic aromatic hydrocarbons (PAH) and the mineralization of three
14C-labeled PAH by the white-rot fungus Pleurotus sp. Florida was investigated. Three concentrations containing 50, 250 or 1250 μg each unlabeled PAH/5 g straw were added
to sterile sea sand. Selected treatments were added subsequently with 14C-labeled pyrene, benzo[a]anthracene or benzo[a]pyrene. The PAH-loaded sea sand was then mixed into straw substrate and incubated. The disappearance of the unlabeled four-to
six-ring PAH: pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene, was determined by high-performance liquid chromatography. After 15 weeks of incubation, the recoveries were less
than 25% for initial amounts of 50 μg (controls above 85%). The recoveries of unlabeled PAH increased in the inoculated samples
with increasing concentrations applied. No correlation could be determined between the number of condensed rings of the PAH
and the recoveries of added PAH. Pleurotus sp. Florida mineralized 53% [14C]pyrene, 25% [14C]benzo[a]anthracene and 39% [14C]benzo[a]pyrene to 14CO2 in the presence of eight unlabeled PAH (50 μg applied) within 15 weeks. During the course of cultivation, Pleurotus sp. Florida degraded more than 40% of the wheat straw substrate. Variation of the initial concentration of PAH did not influence
the extent of degradation of the organic matter.
Received: 16 December 1996 / Received revision: 17 March 1997 / Accepted: 22 March 1997 相似文献
15.
《Biocatalysis and Biotransformation》2007,25(2):219-228
Fungal laccases are useful for several remarkable transformations, such as bioremediation of polycyclic aromatic hydrocarbons (PAHs), synthesis of phenolic-based resins, oxidation of lignin derivatives and others. Most of these substrates are barely water-soluble, and although polar organic co-solvents may be added to enhance their solubility, transformation rates dramatically decrease due to the negative effect of organic solvents on the protein structure. Laccase from Myceliophthora thermophila variant T2 (MtLT2) has been submitted to laboratory evolution in Saccharomyces cerevisiae with the aim of improving activity and stability in organic co-solvents. Some 4500 clones created by random mutagenesis were screened in two rounds of directed evolution. Libraries were explored under increasing concentrations of acetonitrile and ethanol, and several mutants with improved features were purified and further characterised. Turnover rates of MtLT2 in 30% (v/v) acetonitrile and 50% (v/v) ethanol were increased up to 6.5- and 7.5-fold, respectively. The best variants showed similar rates in 20% (v/v) acetonitrile or 30% (v/v) ethanol as the parent type in aqueous media. Mutant laccases were also tested for the oxidation of anthracene in the presence of 20% (v/v) acetonitrile. 相似文献
16.
H. F. Wesp X. Tang R. Edenharder 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2000,472(1-2)
To test the assumption that automobile exhausts contribute to soil mutagenicity, two soils with low levels of mutagenic activities were exposed to traffic exhausts at a heavily charged junction of German motorways (Autobahnen) for 3, 7, 10, 13, 17, 21, and 26 weeks. Indeed, in the presence of a metabolic activation system from rat liver (S9), an average increase of 8 and 9 (4 and 12) revertants per gram per week was found in Salmonella typhimurium TA 98 (TA 100). In the absence of S9, meaningful measurements were impossible on account of a concurrent dose dependent increase of toxicity. No correlation between the increase of mutagenicity and the contents of polycyclic aromatic hydrocarbons (PAH) could be detected. In another series, soils sampled at the roadside and at distances of 10 and 50 m of five roads near Mainz expressed 10–20-fold higher mutagenicity (revertants per gram) under identical test conditions as compared with the average of agricultural soils. Toxic effects, however, again confounded the results and no correlation between the distance from roads and the levels of mutagenicity could be demonstrated. Subsequently, Soxhlet-extraction with the solvent sequence dichloromethane, acetone, and toluene/diethylketone was found to be an optimum procedure for soils at roadsides. The mass balance of solvent fractionation of such soils revealed that <2% each belonged to organic acids and bases, 4% to fractions designed polar neutrals, 8% to polar aromatics, 7% to dichloromethane solubles, and 79% to cylohexane solubles, among them 63% acetone soluble compounds. The major part of mutagenicity (55–65%) was present in the fraction of polar aromatics, followed by polar neutrals and the acetone subfraction of cyclohexane solubles (10% each) summarizing the results obtained with S. typhimurium TA 98, TA 98NR, YG 1021, YG 1024, TA 100, YG 1026, and YG 1029 with and without addition of S9. The modified tester strains, either deficient in nitroreductase (TA 98NR) or overproducing nitroreductase (YG 1021, 1026) or O-acetyl-transferase (YG 1024, 1026), indicated a major contribution of nitroarenes to soil mutagenicity. With respect to mutagenic PAH, high pressure liquid chromatography (HPLC) revealed that >90% of dibenz[a,h]anthracene (4.18 mg/kg soil), benzo[a]pyrene (1.96 mg), benzofluoranthenes (0.14 mg), and benz[a]anthracene (0.18 mg) were present in the acetone subfraction of cyclohexane solubles. Concentrations and mutagenic activities, however, did not correlate. Additional preparative and analytical HPLC of the solvent fractions of polar neutrals and polar aromatics, resulted in the tentative identification of 2-nitrofluorene. Analysis of the vertical profile of soil revealed an increase of mutagenicity per gram from the surface to a maximum at 5–15 cm depth and a subsequent decrease with very little activity remaining deeper than 35 cm. In human lymphocyte cultures, the fraction of polar aromatics, 0.01–0.3 μg/ml, induced 11.27±4.76–20.70±6.19 sister-chromatid exchanges (SCE) per cell in the absence of S9 (solvent control: 10.16±4.83 SCE per cell) and 12.77±6.53–17.87±4.93 SCE per cell in the presence of S9 (solvent control: 8.37±3.92 SCE per cell). However, no activities could be detected in the fractions of polar neutrals and non-polar neutrals. Again, negative results were obtained in the in vivo mouse bone marrow micronucleus assay at 2000 mg/kg p.o. with all fractions. 相似文献
17.
The white-rot fungus Pleurotus ostreatus catalysed some humification of anthracene, benzo[ a ]pyrene and fluoranthene in two polycyclic aromatic hydrocarbon (PAH)-contaminated soils, one from a former manufactured gas facility and one from an abandoned electric coking plant. However, the extent of humification of PAH observed in these experiments was considerably less than that previously reported for other pollutants, such as chlorophenols. Addition of surfactants and related amendments significantly enhanced PAH removal from both soils by P. ostreatus , although humification of PAH was not always enhanced under these conditions. 相似文献
18.
D. Dhamodharan 《Bioremediation Journal》2015,19(4):287-295
Polycyclic aromatic hydrocarbons (PAHs) are known to be toxic to living organisms and have been identified as carcinogenic. In this study, a pathway of surfactant flushing, chemical oxidation, and biological treatment is proposed to remediate the soils polluted with the hydrophobic PAHs. Different surfactants such as Tween 80, Brij 35, sodium dodecyl sulfate (SDS), and polyethylene glycol (PEG) 6000 were tested in order to increase the PAH solubilization from the soil matrix. The maximum desorption efficiency of naphthalene and anthracene were found to be 56.5% and 59%, respectively, when Brij and SDS were used. The soluble PAH in the aqueous phase was amended with sodium thiosulfate (3%) to oxidize the PAH into a more bioavailable form. The chemical oxidation with subsequent biodegradation by Pseudomonas aeruginosa exhibited the relatively high PAH degradation rate (1.24 times higher) when compared with chemical oxidation alone. These results display the efficiency of chemical pretreatment of PAH-contaminated soil for improved bioremediation. 相似文献
19.
Summary Two different quality types of sugar-cane molasses containing a total sugar content of 48%–50% (w/v) and 35%–42% (w/v) were investigated for Zymomonas biothanol production. Molasses concentrations of up to 250 g/l (1:3 dilution) were successfully fermented within 24 h despite a higher salt concentration in the lower grade molasses. Higher molasses concentrations (300 g/l) led to fructose accumulation. The addition of sucrose to a final sugar concentration of 15% (w/v) led to 10% (v/v) ethanol with conversion efficiencies up to 96%. Sorbitol levels were negligible, but increased up to tenfold upon addition of invertase.
Offprint requests to: H. W. Doelle 相似文献
20.
Ethanol, BTEX and microbial community interactions in E-blend contaminated soil slurry 总被引:1,自引:0,他引:1
Akvile Lawrence Susanne Jonsson Gunnar Brjesson 《International biodeterioration & biodegradation》2009,63(6):654-666
Degradation of benzene, toluene, ethylbenzene, m-, p- and o-xylenes (BTEX) and microbial community shifts in soil slurries contaminated with ethanol–gasoline blends (E-blends), containing 10, 50 or 90% (v/v) ethanol (E10, E50 and E90) were studied in soil slurries previously uncontaminated, contaminated by E-blends or ethanol. BTEX originating from E50 degraded fastest whereas from E10 slowest. Among the individual compounds, ethylbenzene degraded fastest (max 30% d−1), and o-xylene slowest (min 1% d−1) during aerobic conditions in previously not contaminated soils. Previous contamination by E-blends increased BTEX degradation significantly (3–19 times) compared with previously uncontaminated soils, whereas previous contamination with ethanol did not show significant difference in BTEX degradation. At least one type of the E-blends during aerobic conditions had a positive effect on total PLFAs (phospholipid fatty acids) and specific PLFAs, i.e. 10Me18:0, 16:1ω6 and cy17:0, but had a negative effect on cy19:0 and 18:2ω6,9c. The effects on total PLFAs, as well as the individual PLFAs, were particularly strong after repeated contamination. The single most affected PLFA was 16:1ω6, which increased 23 times during E10 treatment in soil slurries previously contaminated by E-blends. Altogether, the various E-blends had significantly different effects on BTEX degradation and also on individual PLFAs under aerobic conditions. 相似文献