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1.
Veronica Bianchi Grazia Masciandaro Brunello Ceccanti Serena Doni Renato Iannelli 《Water, air, and soil pollution》2010,210(1-4):187-195
A meso-scale pilot plant was set up to test the efficiency of a phytoremediation technique applied to slightly contaminated marine sediments dredged from the port of Livorno (central Italy). The technique applied involved the use of plants (a grass species, Paspalum vaginatum and a shrub species, Tamarix gallica) and earthworms (Eisenia foetida sp.) in order to recreate an active ecosystem in which plants, micro- and macroorganisms could interact with each other through the rhizosphere, for the adsorption, extraction and/or degradation of pollutants. This system enables plants to grow in a fine textured and salt medium highly unsuitable for plant species, and a physical, chemical and biological amelioration of the matrix was observed at the end of the experimentation (after 9 months). The sediment was bio-physically pre-conditioned by mixing it with calcareous material from excavating activities (5:1?v/v) and applying green compost. The presence of microorganisms in the rhizosphere and the earthworms produced a reduction by about 50% of the initial total petroleum hydrocarbon content. The use of a natural chelator with phyto-hormonal properties (humic substances) showed their capability of forming stable complexes, especially with Pb, and their contribution as an agronomic fertiliser. The combined effect of the P. vaginatum and T. gallica in the extraction of heavy metals from the sediment showed promisingly high percentages of metal effectively extracted in comparison with its available fraction (e.g. available Ni = 6.2%; Ni extracted = 15.7%). The technique proposed could be promising for an operational re-use of dredged marine sediments for agricultural purposes, a suitable final destination for the great majority of these contaminated materials from rivers and harbour docks. 相似文献
2.
Soil Bioremediation: Combination of Earthworms and Compost for the Ecological Remediation of a Hydrocarbon Polluted Soil 总被引：1，自引：0，他引：1
Brunello Ceccanti Grazia Masciandaro Carlos Garcia Cristina Macci Serena Doni 《Water, air, and soil pollution》2006,171(1-4):383-397
A three-dimensional (3D) off-line chemical transport model (CTM) has been used to study an Arctic ozone minihole event in early December 2002, when the meteorological conditon were severely colder than in recent years. The minimum temperatures were below 188 K on 6 December 2002 and remained below 195 K for the entire month. Such temperatures are low enough for the formation of PSCs (polar stratospheric clouds) which were observed by a visible/near infrared solar occultation instrument by the Polar Ozone and Aerosol Measurement (POAM) III experiment. The SLIMCAT model compares well with the depth and evolution of the ozone distribution as observed by the second European Remote Sensing Satellite (ERS-2) Global Ozone Monitoring Experiment (GOME). The combined effect of a very strong and large intrusion of sub-tropical air, and uplifting of air masses of low ozone concentrations from the troposphere plays important role in the fomation of the ozone minihole. The modelled chemical ozone loss rate was relatively fast in the lower stratosphere in the region of frequent PSCs and higher levels of ClO and BrO. The observed PSCs in the vicinity of the minihole supports the model-predicted location of PSCs and chlorine activation. However, ozone miniholes have been attributed almost entirely to dynamical effects due to its short duration. 相似文献
3.
Sodium pyrophosphatc (0·1 m) at pH 7.1 and 37°C extracted a significant fraction of urease from a podzol. Maximum extraction values were obtained after 18 h. The yields of soil organic matter and urease activity during the extraction show a different pattern: the extraction of non-specific organic matter precedes and may facilitate the following extraction of an active urease organo-complex. The urease extracted by pyrophosphate is about 30 40 per cent of the total urease activity, as shown by plotting the urease activity against the population changes of ureolytic microorganisms, both in the original and extracted soil. The number of ureolytic microorganisms is unaffected by pyrophosphate, and the extracted urease is assumed to be extracellular. 相似文献
4.
Summary Purification of soil phosphatase-, urease-, casein- and benzoylarginamide-hydrolysing proteases was obtained by exhaustively ultrafiltering a soil extract using 0.1M pyrophosphate solution at pH 7.1, separating the retained material into fractions of molecular weight higher (AI) and lower (AII) than 105 and eluting the fractions on gel chromatography.Three peaks of phosphatase and urease activity were obtained after gel chromatography of fraction AI on Sephadex G200 using 0.1M pyrophosphate solution as eluant. Only one distinct activity peak was observed when casein- and benzoylarginamide-hydrolysing proteases were assayed in the eluted fractions. Elution diagrams obtained by gel chromatography of fraction AII on Sephadex G100, using a water as eluant, were characterized by one peak each of phosphatase-, casein- and benzoylarginamide-hydrolysing activity and by two peaks of urease activity.Gel chromatography of both AI and AII, generally, but not always, increased specific activity on a C and N basis of derivative fractions. Both proteases showed the highest increase in specific activity due to a marked decrease in organic C and N and an increase in total activity. 相似文献
5.
Pyrophosphate (140 mM, pH 7.1) extracts of two arable soils and one pasture soil were ultrafiltrated separating the extracted material into three fractions: AI with nominal molecular weight (nmw) > 100 kD, AII with nmw between 10 kD and 100 kD and R with nmw < 10 kD. Protease activity was determined in the fractions by using three different substrates: N-benzoyl-l-argininamide (BAA), specific for trypsin; N-benzyloxy-carbonyl-l-phenylalanyl l-leucine (ZPL), specific for carboxypeptidases; and casein, essentially a non-specific substrate. The derivative fractions were also analysed for their amino acid N and humic (HA) and fulvic (FA) acid contents. The organic matter of extracts and derivative fractions obtained from the pasture soil was analysed by isoelectric focusing (IEF) and that of fractions analysed by pyrolysis gas chromatography (Py-GC). Activities of the extract were monitored for their thermal stability and those of the extract and derivative fractions for their optimal pH.Due to the mechanical disintegrating action of sodium pyrophosphate over the humic substances during the fractionation process the amount of total organic C and FA in the fractions was ranked as R > AII > AI. The lowest amino acid N/organic C was found in the R fraction, whereas AII fraction was rich in humic acids, carbohydrates and amino acid N and AI fraction showed the lowest carbohydrate content. At least 70% of the total BAA- and ZPL-hydrolysing activity was associated to particles with nmw higher than 10 kD and at least 30% of these activities were present in particles with nmw higher 100 kD. Casein-hydrolysing activity was quite evenly distributed among the three fractions (AI, AII and R). The extracted protease-organic complexes were resistant to thermal denaturation and some of them showed optimal activity at pH values higher than 10 as a result of the polyanionic characteristics of the humic material surrounding enzyme molecules and of the presence of alkaline protease. Comparison of data obtained in Py-GC analyses and in protease activity suggests that BAA-hydrolysing activity was associated to a highly condensed humic matter and ZPL-hydrolysing activity to less resistant humic substances, while at least some of the extracted casein-hydrolysing activity was present as glyco-proteins not associated to humus. BAA-hydrolysing activity was probably inhibited by fresh organic matter of carbohydrate origin whereas lignin derived organic matter probably inhibited ZPL- and casein-hydrolysing activity. 相似文献
6.
Some techniques commonly used for enzyme purification were unsuitable to purify urease extracted by pyrophosphate from soil. An all-or-none behaviour seemed to be a prominent feature of such experiments but in some instances slight increases of specific activity were observed.The most effective purification of soil urease was achieved by exhaustively ultrafiltrating the soil extract against 0.1 m pyrophosphate at pH 7.1, separating the retained material into fractions of mol. wt. higher (AI) and lower (AII) than 105, followed by gel chromatography.Increases in total activities were observed both after ultrafiltration and gel chromatography. Ultra-filtration increased the total activity of the extracted urease by about 8%. The specific activity of fraction AI increased four fold, that of fraction AII by more than three fold. Fractions obtained by gel chromatography accounted in toto for only 13.5% of the organic-C of the soil extract. Total urease activity increased by 45.6%. Specific activities increased to 6.9–18 times that of the soil extract. 相似文献
7.
Vermicomposting is an eco-biotechnological process that transforms energy-rich and complex organic substances into a stabilized
humus-like product. In a laboratory experiment, Eisenia fetida (Sav.) earthworms were employed to process putrescible sewage sludges into a high-value biofertilizer, very rich in urease
activity and humic-urease complexes (stabilized extracellular enzymes). Extracellular humic-urease complexes were extracted
by a single 24-h extraction at 37 °C using neutral pyrophosphate (0.1 M); then, the extracts were dialysed and characterized
by means of an analytical isoelectric focusing technique. This technique gave a multiplicity of humic bands enzymatically
active, with isoelectric points ranging from 4.8 to 5.6. The results demonstrated that, after an 18-week incubation period,
sewage sludge had undergone a biochemical evolution, which caused a doubling of absolute urease activity and a six-fold increase
in specific activity (activity with reference to the humic C fraction). The biochemical evolution of the vermicompost was
evaluated also from the sharp decrease in pyrophosphate-extractable C and water-soluble C. Stabilization of organic C during
vermicomposting and the activity of humic-urease complexes expressed at low pH values are of extreme importance when organic
wastes are used in acid soils for biochemical restoration purposes.
Received: 10 June 1999 相似文献
8.
F. Gil-Sotres M. C. Trasar-Cepeda C. Ciardi B. Ceccanti M. C. Leirós 《Biology and Fertility of Soils》1992,13(1):25-30
Summary A number of biochemical parameters reflecting biological activity (respiration, ATP, enzyme activities) were determined in 0- to 7-year-old lignite mine soils. C (as CO2) and ATP contents and hydrolytic enzyme activities all increased with soil age. The kinetics of CO2 release showed that both labile and recalcitrant C-bearing substrates were mineralized, the mineralization constant of C decreased with soil age, but were always greater than those of native soils. The percentage of N mineralization, which tended to decrease with soil age, resulted in all cases in a predominance of ammoniacal forms. These findings suggest that since organic C and N accumulated with age in these soils, the C and N cycle is established progressively. 相似文献
9.
C. García T. Hernández F. Costa B. Ceccanti C. Dell'Amico 《Biology and Fertility of Soils》1992,13(2):112-118
Summary Isoelectric focusing was used to characterize the organic matter of composted and uncomposted sewage sludge. The technique was applied to organic matter extracts and to three fractions, obtained by ultrafiltration, with different molecular weights (<103, 103–104, >104). The elution curves of the extracts through Sephadex G-50 revealed a loss in the proportion of organic matter of low molecular weight as composting progressed, together with an enrichment of the high-molecular-weight proportion. Separation into fractions by controlled ultrafiltration proved to be valid, as deduced from the chromatograms obtained by Sephadex G-50 filtration. The extracts of uncomposted sludge showed a greater number of bands with a low isoelectric point than the composted extract, because there were more acidic molecules in the samples that had not undergone humification. The spectrum corresponding to the extract of the 210-day compost showed greater homogeneity with a lower number of bands. A great part of the organic matter extracted with 0.1 M Na4P2O7 at pH 7.1 corresponded to an intermediate molecular weight. The ampholytes at pH 4–6 gave better resolution than those at pH 3.5–10, in the focusing of fractions with the lowest and the greatest molecular weight. A more homogeneous spectrum was observed for the high-molecular-weight fractions from extracts of the 210-day composted sample; in addition, the bands were displaced towards higher isoelectric points, which indicated that the molecules were more condensed, with a minor content of negatively charged groups and a spectrum similar to that of relative fractions of true humic acids. 相似文献
10.
Summary Extracellular benzoyl-l,-argininamide (BAA)-hydrolysing protease was extracted with neutral pyrophosphate from an arable soil and fractionated by membrane ultrafiltration. There were three fractions: A1 (molecular weight > 105), AII (molecular weight 104–105), and R (molecular weight < 104). Analytical isoelectric focusing (IEF) of the fractions was carried out on polyacrylamide gels with a restricted pH gradient of 4.0 to 5.0. Two extracellular proteases characterized soil extract E, with one peak (Ip 4.44) bound to a large amount of humic matter and the other (Ip 4.06) bound to a small amount of humus. Following ultrafiltration, the humus-enzyme complex of extract E (Ip 4.44) split into the fractions AI, AII, and R, and was displaced at Ip values that depended on the electrophysical properties of bound organic matter, whereas that at Ip 4.06 was completely removed from the extract E and accumulated only into the low-molecular-weight fraction R. High recoveries of absolute activity were obtained after IEF of the whole extract E, and fractions AII and R, but only about 50% was recovered from fraction AI.It appears that humic substances have reversible inhibitory effects on extracellular proteases, since the maximum recoveries of activity were obtained from fractions where high amounts of protease non-active organic matter had been removed by IER IEF was able to fractionate humic molecules and purify humic-protease complexes on the basis of smaller differences in Ip, and even smaller differences of 0.05 pH units. The present results show that BAA hydrolysing proteases were preferentially linked with a specific class of humic molecules with an Ip of close to 4.44.Joint program CNR (Italy) — C.S.I.C. (Spain), no. 7, 1985–1986. This paper is part of the doctoral thesis of Prof. M. Bonmati 相似文献