Fungi are important players in natural ecosystems where they are involved in many functions including several ecosystem services. Belowground biodiversity is closely linked to land management and agricultural intensification causes many pressures that lead to soil contamination, also due to repeated application of pesticides. In fact, soil pollution is one of the main threats related to decline of taxonomic and functional biodiversity and of agricultural soils sustainability. In this context, the study of contaminated soil microbial community represents an important step to shed light on environmentally friendly technologies, exploring the untapped potentiality of fungi in bioremediation. Therefore, it is also important to investigate the toxic response of microorganisms to xenobiotic stress in order to acquire more useful information about their tolerance.
Even if the use of Hexachlorocyclohexane (HCH) and 1,1,1-dichlorodiphenyl trichloroethane (DDT) was banned or severely restricted ages ago, its widespread adoption has determined a global and severe environmental contamination. According to estimations, the worldwide consumption of DDT between 1950 and 1963 was approximately 175,000 t/year while it is estimated that around 1.7 and 4.8 million tons of HCH residues are still present all over the world.
The aim of this project is to isolate and identify fungal species occurring in samples from sites contaminated by HCH and DDT. The tolerance of selected fungal species to high concentration of HCH and DDT by using tolerance indices (Rt:Rc (%); T.I. (%)) will be investigated in order to select the best candidates for DDT and HCH biodegradation. The toxicity of these pesticides against organisms from different trophic levels will be assessed. The oxidative stress responses of selected species of microfungi will be investigated in order to explore their toxic responses and maximize the application in bioremediation of contaminated environments.
The importance and the innovative nature of this project is to search in an integrated approach, that allows to analyze various aspects of the microfungi potentiality. The goal is to extent the information about the possibility to use fungi in bioremediation processes.
Additionally, the project can be a good tool to overcome the existing gap between the reported successes of bioremediation on a laboratory scale and the field scale. In fact, a strategy focusing on a site¿s indigenous fungi must first categorize the site¿s fungi and assess them for bioremediation potential before fungal biostimulation or bioaugumentation can proceed. This kind of information can provide a more thorough explanation of the microbial ecology.
Although current literature suggests that various strategies will be used to degrade contaminants in different fungi, degradation mechanisms have not been enough studied. Therefore, the goal is to shed further light on fungal biotransformation in order to identify novel candidate species for bioremediation applications to contaminated sites and provide opportunities for new environmentally friendly, integrated and cost-effective approaches for environmental management and restoration.
It is also important to study the toxic response of fungi to xenobiotic stress in order to acquire more useful information about their tolerance. Therefore, the aim of this study is to investigate the oxidative stress responses due to the presence of HCH and DDT in selected species of saprotrophic soil microfungi.