Fungi as bioresources for remediation of HCH-contaminated soils: from microbial community-level physiological profile to selective isolation in enrichment

The interaction between human activities and global change (including persistent chemicals pollution) poses severe threats for the soil microbiota thus reducing the provision of ecosystem services1. In this context -, -, and -hexachlorocyclohexane (HCH) are highly persistent organic pollutants ofglobal concern, and a severe risk for human health and ecosystem functioning. Soil fungi, thanksto the ability to tolerate, bioaccumulate and biodegrade HCH, are important bioresources as biobased solutions for HCH-contaminated soil remediation. The study area was selected within the National Priority Site “Bacino del Fiume Sacco” in the Metropolitan City of Rome (Italy). Soil cores, up to 1 m of depth, were collected from 2 plots and later divided in topsoil (TS: 0-10 cm) and subsoil (SS: 10-100 cm) samples. The first goal was to characterize the microbial community level physiological profile, so the soil samples were analysed by the Biolog EcoPlateTM Technique2 to compare metabolic activities of the communities at different depths (TS and SS). Moving on, the project focused on the fungal fraction of the microbial community, evaluating the fungal loaddifferences between TS and SS, through the count of the colony forming units (CFUs/dry soil weight). The CFUs results show a higher fungal load in topsoil than that in subsoil by one order of magnitude. To isolate fungal bioresources suitable for HCH degradation, a selective enrichment procedure with a high concentration HCH mixture as the only carbon source, was carried out. At the end of the procedure several species, mainly belonging to Fusarium and Alternaria genera,were isolated and are currently preserved in the Culture Collection of the Fungal Biodiversity Laboratory (FBL) of the Department of Environmental Biology of Sapienza University of Rome. The isolated fungi represent useful bioresources for further studies aimed at the development of mycoremediation application for HCH contaminated soil remediation.