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The adequacy of the Calgary biofilm device, often referred to as the MBEC system, as a high-throughput approach to the production and subsequent characterization of Pleurotus ostreatus biofilms was assessed. The hydroxyapatite-coating of pegs was necessary to enable biofilm attachment, and the standardization of vegetative inocula ensured a uniform distribution of P. ostreatus biofilms, which is necessary for high-throughput evaluations of several antimicrobials and exposure conditions. Scanning electron microscopy showed surface-associated growth, the occurrence of a complex aggregated growth organized in multilayers or hyphal bundles, and the encasement of hyphae within an extracellular matrix (ECM), the extent of which increased with time. Chemical analyses showed that biofilms differed from free-floating cultures for their higher contents of total sugars (TS) and ECM, with the latter being mainly composed of TS and, to a lesser extent, protein. Confocal laser scanning microscopy analysis of 4-day-old biofilms showed the presence of interspersed interstitial voids and water channels in the mycelial network, the density and compactness of which increased after a 7-day incubation, with the novel occurrence of ECM aggregates with an α-glucan moiety. In 4- and 7-day-old biofilms, tolerance to cadmium was increased by factors of 3.2 and 11.1, respectively, compared to coeval free-floating counterparts. [ABSTRACT FROM AUTHOR]

Abstract: The main aim of this study was to assess the ability of producing extracellular phenoloxidases (EPO) of fungi isolated from olive brine wastewater (OBW), the effluent from the debittering process of table olives. Five out of twenty isolates displayed EPO-producing ability as assessed by selective agar plate assays and were all halotolerant. Among them, Citeromyces matritensis (syn. Candida globosa) and Aspergillus fumigatus concomitantly produced laccase and Mn-peroxidase (MnP) activities. Candida boidinii and Candida bombi, instead, only produced laccase and Candida diddensiae only released MnP. Both C. matritensis and A. fumigatus, grown in shaken cultures on OBW, maintained their EPO-producing ability and removed phenols by 52.3 and 82.3%, respectively, after 10d incubation in the non-supplemented effluent. These results might suggest the possible use of these strains in the treatment of other saline phenol-rich effluents, such as pickling and tannery wastewater. [Copyright &y& Elsevier]

Different applications of spent Agaricus bisporus substrate (SAS), a widespread agro-industrial waste, were investigated with respect to the remediation of a historically polluted soil with Polycyclic Aromatic Hydrocarbons (PAH). In one treatment, the waste was sterilized (SSAS) prior to its application in order to assess its ability to biostimulate, as an organic amendment, the resident soil microbiota and ensuing contaminant degradation. For the other treatments, two bioaugmentation approaches were investigated; the first involved the use of the waste itself and thus implied the application of A. bisporus and the inherent microbiota of the waste. In the second treatment, SAS was sterilized and inoculated again with the fungus to assess its ability to act as a fungal carrier. All these treatments were compared with natural attenuation in terms of their impact on soil heterotrophic and PAH-degrading bacteria, fungal growth, biodiversity of soil microbiota and ability to affect PAH bioavailability and ensuing degradation and detoxification. Results clearly showed that historically PAH contaminated soil was not amenable to natural attenuation. Conversely, the addition of sterilized spent A. bisporus substrate to the soil stimulated resident soil bacteria with ensuing high removals of 3-ring PAH. Both augmentation treatments were more effective in removing highly condensed PAH, some of which known to possess a significant carcinogenic activity. Regardless of the mode of application, the present results strongly support the adequacy of SAS for environmental remediation purposes and open the way to an attractive recycling option of this waste. [ABSTRACT FROM AUTHOR]

Fenton-like treatment (FLT) is an ISCO technique relying on the iron-induced H 2 O 2 activation in the presence of additives aimed at increasing the oxidant lifetime and maximizing iron solubility under natural soil pH conditions. The efficacy of FLT in the clean-up of hydrocarbon-contaminated soils is well established at the field-scale. However, a better assessment of the impact of the FLT on density, diversity and activity of the indigenous soil microbiota, might provide further insights into an optimal combination between FLT and in-situ bioremediation (ISB). The aim of this work was to assess the impacts of FLT on the microbial community of a diesel-contaminated soil collected nearby a gasoline station. Different FLT conditions were tested by varying either the H 2 O 2 concentrations (2 and 6%) or the oxidant application mode (single or double dosage). The impact of these treatments on the indigenous microbial community was assessed immediately after the Fenton-like treatment and after 30, 60 and 90 d and compared with enhanced natural attenuation (ENA). After FLT, a dramatic decrease in bacterial density, diversity and functionality was evident. Although in microcosms with double dosing at 2% H 2 O 2 a delayed recovery of the indigenous microbiota was observed as compared to those subjected to single oxidant dose, after 60 d incubation the respiration rate increased from 0.036 to 0.256 μg C CO 2 g −1 soil h −1 . Irrespective of the oxidant dose, best degradation results after 90 d incubation (around 80%) were observed with combined FLT, relying on double oxidant addition, and bioremediation. [ABSTRACT FROM AUTHOR]

Abstract: An experimental biofuel wood chip storage site was studied, as a potential fungal “reservoir,” by means of quantitative and qualitative assessments of airborne fungal spores. Fungal load in the bio-aerosol, determined through active and passive methods, declined with the distance from wood piles. Occupational exposure was comparatively evaluated when two specific operational tasks, manual and mechanized handling, were performed. Under the conditions tested, the manual operators were more exposed to the airborne fungal spores (4864 ± 580 CFU m−3 air). The collected spores were identified as belonging to species of the genera Alternaria, Aspergillus, Penicillium, Fusarium, Cladosporium, Pleospora, Cochliobolus, Epicoccum, Absidia, and Trichoderma. Most prevalent were the genera Alternaria and Cladosporium, with the highest percentages of occurrence (30 and 12%, respectively). To the best of our knowledge, this is the first work reporting the identification through molecular methods of airborne fungi released during the handling of wood chip biofuel biomass. [Copyright &y& Elsevier]