Potential of the microbial community present in an unimpacted beach sediment to remediate petroleum hydrocarbons

The potential of the microbial communities present in the intertidal zone of an unimpacted beach (a beach that did not suffer any significant oil spill) to degrade hydrocarbons was investigated. For that, laboratory-based microcosms (50-ml flasks) were set up with sandy beach sediment spiked with crude oil and incubated with local seawater for 15 days in the dark. Three bioremediation treatments were tested (biostimulation (BS), autochthonous bioaugmentation (AB), and combined treatment of biostimulation + bioaugmentation (BS + AB)) and the results were compared with natural attenuation (NA). Visual inspection showed clearly an oil solubility increase (confirmed by a higher hydrocarbons concentration in supernatant solutions) for all tested treatments when compared to NA. Significant degradation of the oil, shown by different profiles of petroleum hydrocarbons, was also observed for the different treatments particularly for BS + AB. Therefore, the microbial community of this unimpacted beach sediment could respond to an oil spill, degrading hydrocarbons. But to increase the natural attenuation pace, obtained results indicated that BS + AB is an appropriate approach for the bioremediation of beaches recently impacted by an oil spill. The autochthonous microbial cultures can be obtained “before” or “after” the contamination of the target site, being inoculated into the site right after it contamination.     

A new method for testing the sensitivity of active biomonitoring: an example of its application to a terrestrial moss

For the first time, the concepts of limit of detection and limit of quantification, commonly used in analytical chemistry, are applied to the field of active biomonitoring with terrestrial mosses, using the controls as blanks so that the limits indicate the error associated with the transplant technique. The application of these concepts to data corresponding to Hg concentrations in the surroundings of a chlor-alkali plant and a power plant, makes interpretation of the results easier by providing better spatial and temporal coherence. This procedure may allow improvement in the standardization of active biomonitoring techniques as it is applicable to all kinds of biomonitors. One disadvantage of the application of the limit of detection and limit of quantification is that they only take into account the alpha error, or risk of false positives, and do not take into account the beta error, or risk of false negatives.     

不同碳源条件下草菇内切型纤维素酶基因（eg1）转录表达的分析

利用Northernblot方法分析了不同碳源条件下草菇切型纤维素酶基因(eg1)的表达.结果发现,在含有纤维素的液体培养基中生长10d,eg1在草菇菌丝中有高效表达;纤维二糖、α-乳糖、β-乳糖,也能诱导eg1的表达,但和纤维素相比,eg1的表达量相对较低,并且它们的诱导效应在加入这类糖12h后迅速减弱;槐糖和龙胆二糖的诱导作用非常弱.在天然稻草为基质的固体栽培料生长时,草菇eg1的表达和草菇菌丝生长与出菇相对应,在菌丝生长期(d8)可见eg1的表达,d12时菌丝已长满,表达减弱,在出菇及菇体的分化及增大期,eg1的表达量逐渐增强,在成熟期达到最高水平;表明在草菇菇体发育中需要更多碳源及能源的补充,eg1在这方面起着非常重要的作用.图4参14     

Physiological responses to atmospheric fluorine pollution in transplants of Pseudoscleropodium purum

Transplants of the moss Pseudoscleropodium purum were placed under shade, and with an auto irrigation system, at five sites in the surroundings of an aluminium smelter to enable study of the possible effects of F on different physiological parameters after exposure periods of 28 and 56 days. Reference thresholds for the content of Chl a+b and for the pigment indexes of Chl a/b and D665/D665a were established with the data corresponding to 22 transplants of each duration of exposure, at seven sites where there was little or no contamination by F. The highest determination coefficients for the levels of F in moss were those obtained for chlorophyll content (Chl a+b) and the D665/D665a pigment index, with the effects being most evident in the transplants exposed to the contamination for 56 days.     

Decolourization of synthetic dyes by Trametes hirsuta in expanded-bed reactors

The present paper studies the decolourization of different synthetic dyes (Indigo Carmine, Bromophenol Blue, Methyl Orange and Poly R-478) by the white-rot fungus Trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. Dye decolourization was performed in both batch and continuous mode. Batch cultivation led to high decolourization percentages in a short time (100% for Indigo Carmine in 3h and 85% for Bromophenol Blue in 7 h). As for continuous cultivation, different hydraulic retention times (HRT) were studied (0.8, 1, 1.5 and 3d). The highest decolourization percentages were obtained operating at a HRT of 3d, especially for the dyes Methyl Orange and Poly R-478 (81.4% and 46.9%, respectively). This is a very interesting result, since there are few studies dealing with the continuous decolourization of dyes at bioreactor scale by fungal laccases.     

Coupling of 2,4,6-trinitrotoluene (TNT) metabolites onto humic monomers by a new laccase from Trametes modesta

During degradation of trinitrotoluene (TNT) by Trametes modesta, addition of humic monomers prevented the accumulation of all major stable TNT metabolites (aminodinitrotoluenes [AMDNT]) by at least 92% in the presence of 200 mM ferulic acid and guaiacol. Acute toxicity tests with individual TNT metabolites and in T. modesta cultures supplemented with 200 microM TNT demonstrated that the TNT biodegradation process lead to less toxic metabolites. Toxicity decreased in the order TNT>4-HADNT (4-hydroxylaminodinitrotoluene)>2-HADNT>2,6-DNT (2,6-dinitrotoluene)>2',2',6,6-azoxytetranitrotoluene>4-AMDNT>2-AMDNT>2,4-diamninonitrotoluene (2,4-DAMNT) while 2,4-DNT and 2,6-DAMNT were the least toxic. Ferulic acid is the best candidate for immobilization TNT biodegradation metabolites since it prevented the accumulation of AMDNTs in cultures during TNT biodegradation and its products were less toxic. All humic monomers were very effective in immobilizing 2-HADNT [100%], 4-HADNT [100%] and 2,2,6,6-azoxytetranitrotoluene [100%]. Two distinct laccase isoenzymes (LTM1 and LTM2) potentially involved in immobilization of TNT degradation products were purified to electrophoretic homogeneity. LTM1 and LTM2 have molecular weights of 77.6 and 52.5 kDa, are 18% and 24% glycosylated, have pI values of 3.6 and 4.2, respectively. Both enzymes oxidized all the typical laccase substrates tested. LTM1 showed highest kinetic constants (K(m)=0.03 microM; K(cat)=8.8 4x 10(7)s(-1)) with syringaldazine as substrate.     

Traffic and catalytic converter - related atmospheric contamination in the metropolitan region of the city of Rio de Janeiro, Brazil

In this work, 24-h PM10 samples were collected in Rio de Janeiro, Brazil, and analysed for trace elements (Cd, Ce, Cu, La, Mo, Ni, Pb, Pd, Rh, Sb and Sn). The sampling was carried out at five locations (Bonsucesso; Centro, downtown city; Copacabana; Nova Igua?u and Sumaré) with different traffic densities and anthropogenic activities. An analytical method based on the EPA method for the determination of trace elements in airborne particulate matter (PM), using ultrasonic-assisted extraction and inductively coupled plasma mass spectrometry (ICP-MS) was applied. Our results suggest that vehicular traffic is the most important source of environmental pollution at the studied sites. The presence of Mo, Pd and Rh in the analysed filters reflects an additional source of pollution caused by the erosion and deterioration of automotive catalytic converters.     

Suitability of Scirpus maritimus for petroleum hydrocarbons remediation in a refinery environment

Purpose  

In the ambit of a project searching for appropriate biological approaches for recovering a refinery soil contaminated with petroleum hydrocarbons (PHC), we compared results obtained in the absence and in the presence of the salt marsh plant Scirpus maritimus or Juncus maritimus or an association of these two plants, which were tested in the refinery environment. Synergistic effects caused by addition of a non-ionic surfactant and/or a bioaugmentation product were also investigated. Major challenges of this study were: field conditions and weathered contamination.     

Suitability of oil bioremediation in an Artic soil using surplus heating from an incineration facility

A 168-day period field study, carried out in Sisimiut, Greenland, assessed the potential to enhance soil remediation with the surplus heating from an incineration facility. This approach searches a feasible ex situ remediation process that could be extended throughout the year with low costs. Individual and synergistic effects of biostimulation were also tested, in parallel. An interim evaluation at the end of the first 42 days showed that biostimulation and active heating, as separate treatments, enhanced petroleum hydrocarbon (PHC) removal compared to natural attenuation. The coupling of both technologies was even more effective, corroborating the benefits of both techniques in a remediation strategy. However, between day 42 and day 168, there was an opposite remediation trend with all treatments suggesting a stabilization except for natural attenuation, where PHC values continued to decrease. This enforces the “self-purification” capacity of the system, even at low temperatures. Coupling biostimulation with active heating was the best approach for PHC removal, namely for a short period of time (42 days). The proposed remediation scheme can be considered a reliable option for faster PHC removal with low maintenance and using “waste heating” from an incineration facility.