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Fungi play irreplaceable roles for ecosystem functioning. They may adopt different lifestyles, for example saprotrophs, symbionts or parasites: some species are cosmopolitan with a wide distribution and others, thanks to their ecological plasticity, may adapt to harsh environments precluded to most of life forms. In stressing conditions, their role is even more crucial for the recycling of organic matter or favoring nutrients uptake. When the conditions become really extreme and competition is low, fungi focus on extremotolerance and evolve peculiar competences to exploit natural or xenobiotic resources in the particular constrains imposed by the environment. This paper focuses on three different cases of fungal life in the extremes: hydrocarbon-polluted sites, extremely acidic substrates, and littoral dunes, aiming to give few but significant examples of the role of these fascinating organisms in peculiar habitats and the valuable biotechnological potentialities of the abilities they have evolved in response to such constrains. Keywords

Biodegradable plastics are mostly applied in packaging materials (e.g., shopping bags), waste collection bags, catering products, and agricultural applications. In this last case, degradation takes place directly in soil where biodegradable plastic products are intentionally left after use (e.g., mulch films for weeds control). Due to the growing volumes of biodegradable polymers and plastics, interest in their environmental safety is increasing and more research is carried out. Some attempt has been made to apply biotests, used in other sectors of environmental sciences, in the assessment of biodegradable plastics safety. In this work, the quality of soils after biodegradation of the bioplastics Mater-Bi has been assessed with a large array of biotests based on model organisms representative of the different trophic levels in the food chains of the edaphic and aquatic ecosystems. Mater-Bi was degraded under controlled conditions for 6 months at a 1% concentration. The selected organisms included bacteria and protozoa (Vibrio fischeri and Dictyostelium discoideum, respectively), the green alga Pseudokirchneriella subcapitata, plants (the monocotyledon Sorghum saccharatum and the dicotyledon Lepidium sativum), and invertebrates animals (Daphnia magna, a freshwater crustacean, and the Oligochaeta earthworm Eisenia andrei), using both acute and chronic endpoints. The results of the applied ecotoxicological tests showed that the Mater-Bi materials tested at very high doses did not affect the soil quality. Soil exposed to Mater-Bi has no noxious effects on edaphic organisms; in particular, mono and dicotyledon plants results, indicate that Mater-Bi plastic products are innocuous for agricultural uses. The use of more sensitive chronic endpoints allows to exclude possible effects at population level. This is the first time that such a comprehensive approach is applied to the assessment of possible ecotoxicity effects induced by biodegradable plastics in soil and represents a possible starting point for improved standardized testing schemes.

Two distinct extracellular lipases were obtained from Penicillium solitum 194A, isolated from domestic compost, and Cladosporium cladosporioides 194B, isolated from dairy wastewater. These alkaline enzymes had molecular masses of 42 and 30 kDa, respectively. The P. solitum 194A lipase differed in mass from previously reported enzyme, indicating that it is a novel lipase, and indicating that penicillia can secrete lipase isoenzymes. The C. cladosporioides lipase was more active on esters of medium-chain acids, whereas the P. solitum lipase was more active on longer chained substrates. The C. cladosporioides enzyme displayed higher thermal stability than the P. solitum lipase, preserving full activity up to 48 °C and showing a T50 (10 min) of 60 °C. Their different catalytic properties and good protein stability should make these enzymes suitable for biotechnological applications. Furthermore, the combined use of these two fungal strains may prove to be valuable in lipid-rich waste management.

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