Grazia Cecchi

Native fungi as metal remediators: Silver myco-accumulation from metal contaminated waste-rock dumps (Libiola Mine, Italy)

ABSTRACT Metal contamination constitutes a major source of pollution globally. Many recent studies emphasized the need to develop cheap and green technologies for the remediation or reclamation of environmental matrices contaminated by heavy metals. In this context, fungi are versatile organisms that can be exploited for bioremediation activities. In our work, we tested silver (Ag) bioaccumulation capabilities of three microfungal strains (Aspergillus alliaceus Thom & Church, Trichoderma harzianum Rifai, Clonostachys rosea (Link) Schroers, Samuels, Seifert & W. Gams) isolated from a silver polluted site. The aim was to select silver tolerant native strains and test their potential silver uptake. Among the three species tested, T. harzianum was the most efficient strain to tolerate and accumulate silver, showing an uptake capability of 153 mg L−1 taken at the Ag concentration of 330 mg L−1. Our study highlights the potential use of native microfungi spontaneously growing in sulphide-rich waste rock dumps, for silver bioaccumulation and bioremediation.

Assessment of Ni accumulation capability by fungi for a possible approach to remove metals from soils and waters

ABSTRACT Abandoned industrial sites and mines may constitute possible hazards for surrounding environment due to the presence of toxic compounds that may contaminate soils and waters. The possibility to remove metal contaminants, specifically nickel (Ni), by means of fungi was presented exploiting a set of fungal strains isolated from a Ligurian dismissed mine. The achieved results demonstrate the high Ni(II) tolerance, up to 500 mg Ni l−1, and removal capability of a Trichoderma harzianum strain. This latter hyperaccumulates up to 11,000 mg Ni kg−1, suggesting its possible use in a bioremediation protocol able to provide a sustainable reclamation of broad contaminated areas.

Biodiversity in Metal-Contaminated Sites – Problem and Perspective – A Case Study

The primary causes of soil contamination are intensive industrial activities and inade‐ quate waste disposal and treatment (although these categories vary widely across Eu‐ rope) [1]. Good knowledge of the content and variability of metals in soils linked to both the contribution of parent rock (lithogenic sources) and human activities (anthropogenic sources) is also necessary for evaluating metal pollution. These tasks are particularly difficult to achieve in ancient populated areas, such as the European Mediterranean region, where unpolluted soils are almost impossible to find [2, 3]. Among anthropogenic sour‐ ces, mining activities are the fourth largest source of land pollution (e.g., 7% of the National Priority (Superfund) Sites in the USA; [4]).

Penicillium expansum Link strain for a biometallurgical method to recover REEs from WEEE

Due to the wide range of applications in high-tech solutions, Rare Earth Elements (REEs) have become object of great interest. In the last years several studies regarding technologies for REE extraction from secondary resources have been carried out. In particular biotechnologies, which use tolerant and accumulator microorganisms to recover and recycle precious metals, are replacing traditional methods. This paper describes an original biometallurgical method to recover REEs from waste electrical and electronic equipment (WEEE) by using a strain of Penicillium expansum Link isolated from an ecotoxic metal contaminated site. The resulting product is a high concentrated solution of Lanthanum (up to 390ppm) and Terbium (up to 1520ppm) obtained from WEEE. Under this perspective, the proposed protocol can be considered a method of recycling exploiting biometallurgy. Finally, the process is the subject of the Italian patent application n. 102015000041404 submitted by the University of Genoa.

Another possible risk for the Mediterranean Sea? Aspergillus sydowii discovered in the Port of Genoa (Ligurian Sea, Italy)

Aspergillus sydowii is a cosmopolitan fungus that has been responsible for the mass destruction of coral in the Caribbean Sea over the last 15years. To our knowledge, this study has found the first case of A. sydowii in the Mediterranean Sea, in marine-bottom sediments, water and calcareous shells of bivalve molluscs sampled during a campaign to characterise the mycobiota in the Port of Genoa (Italy). The area is characterised by adverse environmental conditions (high turbidity, organic pollution and high concentrations of phosphorus and nitrogen compounds). These parameters, in combination with a rising temperature, could contribute to A. sydowii bloom and dispersal. This fungal strain may have been imported into the Port of Genoa in the bilge water of vessels or by torrent input. This work represents the first step in the implementation of a monitoring programme to safeguard calcareous sponges and sea fan corals endemic in the Mediterranean Sea.

Fungal characterisation of a contaminated marine environment: the case of the Port of Genoa (North-Western Italy)

ABSTRACT Nowadays, little information is available about how and if the contaminants may impact on the presence of marine fungi. Indeed, many environmental factors may facilitate the presence of specific fungal taxa. This paper deals with the mycodiversity of 22 stations characterised by contaminated seawaters of the Port of Genoa (North-Western Italy). Several substrates were taken into account and 319 vital strains were isolated belonging to 20 genera and 47 species. The most common genera were Aspergillus, Fusarium, Penicillium and Trichoderma. The fungal richness and mycodiversity were also evaluated and both appeared significantly high in most of these contaminated stations.

Gypsum Biomineralization in Sulphide-rich Hardpans by a Native Trichoderma harzianum Rifai Strain

ABSTRACT Natural acid mine drainage affects abandoned sulfide mines worldwide, causing hardpan formation and heavy metal leaching. Hardpans are characterized by very low permeability, thus representing a significant limiting factor for oxygen and water circulation in the rhizosphere. Our work shows the results concerning the gypsum biomineralization capability of a native Trichoderma harzianum Rifai strain in sulfide -rich hardpans. Two months after the fungal inoculum, hardpan clasts resulted, completely covered by T. harzianum mycelium, where newly formed gypsum crystals occur. Our study provided the first evidence about interaction between T. harzianum and sulfide -mineralized hardpans as well as about its influence on gypsum genesis.

A mycological baseline study based on a multidisciplinary approach in a coastal area affected by contaminated torrent input

Fungi include a vast group of eukaryotic organisms able to colonise different natural, anthropised and extreme environments, including marine areas contaminated by metals. The present study aims to give a first multidisciplinary characterisation of marine bottom sediments contaminated by metals (Cd, Co, Cr, Cu, Ni, and Zn), originating in the water leakage from an abandoned Fe-Cu sulphide mine (Libiola, north-western Italy), and evaluate how the chemical and physical parameters of water and sediments may affect the benthic fungal communities. Our preliminary results showed the high mycodiversity of the marine sediments studied (13 genera and 23 species of marine fungi isolated), and the great physiological adaptability that this mycobiota evolved in reaction to the effects of the ecotoxic bottom sediment contamination, and associated changes in the seawater parameters.

The Geological Roles Played by Microfungi in Interaction with Sulfide Minerals from Libiola Mine, Liguria, Italy

ABSTRACT The potential role played by fungi in the weathering of sulfide abandoned mines and waste rock dumps is scarcely investigated, yet. In particular microfungi may produce biofilms that work as sites of metals and minerals precipitation. This study aimed to investigate interactions, bioalteration, and biocorrosion between three microfungi (Trichoderma harzianum group, Penicillium glandicola, P. brevicompactum) isolated from the Libiola sulfide mine (Liguria, Italy) and pyrite-rich mineralizations occurring within the waste rock dumps. After six weeks of incubation, Environmental Scanning Electron Microscope (ESEM) analyses showed how single pyrite crystals were completely corroded and altered by all the selected species. These results represent the first step to establish that fungi play a central role in the biogeochemical cycles of extreme and contaminated sites such as sulfide mines, and that they actively contribute to the evolution of the degraded ecosystem to more harmonized scenery.

Post-mortem fungal colonization pattern during 6 weeks: Two case studies

The present study reports the mycological data collected from two corpses preserved in controlled conditions and monitored for 6 weeks at the mortuary. On the whole during the monitoring more than 70 fungal CFU (Colony Forming Units) were sampled from the corpses. The data collected were used to map the body fungal colonization of the corpses during 6 weeks. The two body maps show a huge difference between these cases, mainly due to the perimortem conditions. In particular, in the case one the facial area colonised by fungi rose from 15% to 63% in six weeks, while the fungal colonization of case two was about 1% for the whole monitoring period. This work shows, for the first time, the data about the pattern of colonization and distribution of fungi on real corpses after death and argues about the influence of perimortem settings on fungal colonization. Moreover, the paper suggests exploiting the study of fungal colony development and maturation to assess post-mortem interval (PMI).