Understanding fungal functional biodiversity during the mitigation of environmentally dispersed pentachlorophenol in cork oak forest soils

Pentachlorophenol (PCP) is globally dispersed and contamination of soil with this biocide adversely affects its functional biodiversity, particularly of fungi - key colonizers. Their functional role as a community is poorly understood, although a few pathways have been already elucidated in pure cultures. This constitutes here our main challenge - elucidate how fungi influence the pollutant mitigation processes in forest soils. Circumstantial evidence exists that cork oak forests in N. W. Tunisia - economically critical managed forests are likely to be contaminated with PCP, but the scientific evidence has previously been lacking. Our data illustrate significant forest contamination through the detection of undefined active sources of PCP. By solving the taxonomic diversity and the PCP-derived metabolomes of both the cultivable fungi and the fungal community, we demonstrate here that most strains (predominantly penicillia) participate in the pollutant biotic degradation. They form an array of degradation intermediates and by-products, including several hydroquinone, resorcinol and catechol derivatives, either chlorinated or not. The degradation pathway of the fungal community includes uncharacterized derivatives, e.g. tetrachloroguaiacol isomers. Our study highlights fungi key role in the mineralization and short lifetime of PCP in forest soils and provide novel tools to monitor its degradation in other fungi dominated food webs. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd

Exploring the role of the catalytic support sorption capacity on the hydrodechlorination kinetics by the use of carbide-derived carbons

This work aims at evaluating the effect of the catalytic support sorption capacity on the hydrodechlorination (HDC) process. Carbide-derived carbons (CDCs) have been selected for such goal as their high purity and tunable pore structure makes them a suitable carbon model material. CDCs were synthesized from TiC by chlorination at different extraction temperatures (800–1300 °C) in order to selectively modify their pore structure and crystallinity. Afterwards, the catalysts were produced using a three step process of sulfuric acid treatment, ion-adsorption of palladium precursor and gas phase reduction. Pd/TiC-CDC (1% wt.) catalysts were tested in the HDC of 4-chlorophenol (4-CP) in both aqueous and organic phases under ambient conditions (30 °C, 1 atm, [4-CP]0 = 2.9 mmol L−1, [Pd-TiC-CDC] = 1 g L−1, 50 N mL H2 min−1). The experimental results were successfully fitted by an expanded kinetic model which accounts for consecutive reaction and sorption processes in parallel, allowing to deduce true HDC kinetic constants. The sorption capacity of the support was found to determine the HDC rates in aqueous phase. In this sense, those catalysts showing the highest surface areas and lowered ordered structures led to higher HDC rates, confirming that a high surface density of 4-CP onto the catalyst surface enhances significantly the HDC reaction. The optimum catalyst (Pd/TiC-CDC-1000) led to the complete conversion of 4-CP in 15 min at a HDC rate of 4.1 × 10−2 L s−1 gcat −1The authors gratefully acknowledge the funding of the German Research Council (DFG), which within the framework of its “Excellence Initiative” supports the Cluster of Excellence “Engineering of Advanced Materials” (www.eam.fau.de) at the University of Erlangen-Nurember