Exploiting wood rotting fungi as tools to enhance the bioremediation of an artificially polycyclic aromatic hydrocarbon polluted soil.

SAPARRAT, M.C.N.; DEL PANNO M.T.; DI CLEMENTE N

Lyon

Conferencia; AquaConSoil - 14th International Conference; 2017

Exploitingwood rotting fungi as tools to enhance the bioremediation of an artificiallypolycyclic aromatic hydrocarbons polluted soil.Di Clemente, N. A.1;Del Panno, M. T. 1 y Saparrat, M. C. N.21 Centrode Investigación y Desarrollo en Fermentaciones Industriales (CINDEFI), LaPlata, Buenos Aires, Argentina.2 Instituto de Fisiología Vegetal (INFIVE), LaPlata, Buenos Aires, Argentina.e-mail: nataliadiclemente@hotmail.comTwo main groups of fungi belonging to phylumBasidiomycota that attack wood may be distinguished as white (WRF) or brown(BRF) ones. WRF thanks to their extracellular, oxidative enzymes, have abilityto degrade lignin as well as cellulose and hemicellulose. BRF degrade celluloseand hemicellulose present in wood after only a partial modification of ligninby a nonenzymatic Fenton-type catalytic system. However, all these wood rottingfungi have several mechanisms to transform and detoxify environmentalchemicals. Although they are potential agents in bioremediation strategies forcontaminated soils, up to now most of the data available are from axeniccultures, so further work is required to study their capacities in nonsterilesoil and taking into account the natural variables and their practice applicabilityin systems at large-scale or at field. Initially we analysed the ability of the WRF Coriolopsis rigida LPSC 232, Peniophora albobadia LPSC 285, Gelatoporia subvermispora FBCC 313 and Grammothele subargentea LPSC 436 as wellas the BRF Gloeophyllum sepiariumLPSC 735 to degrade and tolerate phenanthrene (Phe, 30 mg %) when supplementedto agar (0.8 %) basal medium or one supplemented with carboxymethyl-cellulose(CMC) at 1 %. The isolates LPSC 436 and LPSC 735, which tolerated Phe in a 70 %and 50 % respectively compared to control cultures, showed Phe-degradingcapacity. However, the isolate LPSC 735 was the one with higher cellulolyticability, being unaffected by the presence of Phe. In addition, thecoinoculation of the fungi LPSC 436 and LPSC 735 showed a synergistic effect onthe degradation of PAHs in agar plate. Then, on a microcosm system containing anartificially contaminated soil with 2500 ppm of Phe and using wheat straw as afungal carrier and as nutrient sources, the degradative ability of both fungiwas analysed, either individually (axenic) and through their coinoculation. Anabiotic control was done in parallel using non-inoculated sterile wheat straw. Also the effect of the autochthonous soilmicrobial community was evaluated through similar microcosms but using either sterilisedor non-sterilised soil.  After 90 days, a significant removal of Phe wasdetected in sterile soil microcosms inoculated with LPSC 735. The coinoculatedsoil showed a delay in the degradation activity, becoming effective after 120days. Since both fungi were able to decrease Phe levelseven in unsterile soil microcosms after 30 days, a synergistic interactionbetween inoculated fungi and the autochthonous microbiota might be implicated. AlthoughPhe elimination was also delay when the fungi were coinoculated, which wasdetected after 90 days, the soil microbial community was unable to counter thecompetition between the inoculated fungi.Based on these preliminary results and applying the same study system,we are now evaluating the total hydrocarbon contentand phytotoxicity of an artificially contaminated soil with a petrochemicalsludge (100 ppm PAH) at 5 and 10 % (w/w) after 30, 60 and 90 days of the fungalinoculation as well as different enzymatic activities relation to degradativeprocesses.