There is a growing awareness in society of the potential environmental problems associated with climate change. Although there has been a slowdown in the global warming rate in recent years (1998-2012) compared to previous decades (1951-2012), the planet continues to accumulate heat (IPCC, 2014). The mean air temperature is expected to increase by more than 2.3°C by 2046-2065 (Brown & Caldeira, 2017). In addition, an increase in the intensity and frequency of extreme weather events, such as

Antarctic environments are characterized by polar climate, making it difficult for the development of any form of life. The biogeochemical cycles and food web in such restrictive environments may be exclusively formed by microorganisms. Polar mycological studies are recent and there is much to know about the diversity and genetic resources of these microorganisms. In this sense, the molecular taxonomic approach was applied to identify 129 fungal isolates from marine and terrestrial samples collected from the King George Island (South Shetland Islands, Maritime Antarctic). Additionally, the production of cold-adapted enzymes by these microorganisms was evaluated. Among the 129 isolates, 69.0% were identified by ITS-sequencing and affiliated into 12 genera. Cadophora, Geomyces, Penicillium, Cosmospora, and Cladosporium were the most abundant genera. Representatives of Cosmospora were isolated only from terrestrial samples, while representatives of the others genera were recovered from marine and terrestrial samples. A total of 29, 19, and 74 isolates were able to produce ligninolytic enzymes, xylanase, and l-asparaginase, respectively. Representatives of Cadophora showed great ability to produce lignin peroxidase (LiP) and laccase at 15.0 °C in liquid medium, while representatives of Penicillium and non-identified fungi were the best producers of xylanase and l-asparaginase at 20.0 °C. The high number of fungi able to produce enzymes at moderate temperature reveals their potential for industrial production and biotechnological applications. The present study broadens the knowledge of fungal diversity associated with the southern polar region. Additionally, data from molecular taxonomy suggest that two filamentous fungi may be considered as potential new species.

Myceliophthora thermophila JCP 1-4 produces avicelase (not commonly found among fungi; important to hydrolyse crystalline cellulose) and a β-glucosidase resistant to glucose inhibition, interesting characteristics for saccharification experiments.

Thermophilic fungi are of wide interest due to their potential to produce heat-tolerant enzymes for biotechnological processes. However, the taxonomy of such organisms remains obscure, especially given new developments in the nomenclature of fungi. Here, we examine the taxonomy of the thermophilic fungi most commonly used in industry in light of the recent taxonomic changes following the adoption of the International Code of Nomenclature for Algae, Fungi and Plants and also based on the movement One Fungus = One Name. Despite the widespread use of these fungi in applied research, several thermotolerant fungi still remain classified as thermophiles. Furthermore, we found that while some thermophilic fungi have had their genomes sequenced, many taxa still do not have barcode sequences of reference strains available in public databases. This lack of basic information is a limiting factor for the species identification of thermophilic fungi and for metagenomic studies in this field. Based on next-generation sequencing, such studies generate large amounts of data, which may reveal new species of thermophilic fungi in different substrates (composting systems, geothermal areas, piles of plant material). As discussed in this study, there are intrinsic problems associated with this method, considering the actual state of the taxonomy of thermophilic fungi. To overcome such difficulties, the taxonomic classification of this group should move towards standardizing the commonly used species names in industry and to assess the possibility of including new systems for describing species based on environmental sequences.