RESUMEN
Cold-adapted microorganisms can produce enzymes with activity at low and mild temperatures, which can be applied to environmental biotechnology. This study aimed to characterize 20 Antarctic fungi to identify their genus (ITS rDNA marker) and growth temperatures and evaluate their ability to decolorize and detoxify the textile dye indigo carmine (IC). An individual screening was performed to assess the decolorization and detoxification of IC by the isolates, as well as in consortia with other fungi. The isolates were affiliated with seven ascomycete genera: Aspergillus (n = 4), Cosmospora (n = 2), Leuconeurospora (n = 2), Penicillium (n = 3), Pseudogymnoascus (n = 6), Thelebolus (n = 2), and Trichoderma (n = 1). The two isolates from the genus Leuconeurospora were characterized as psychrophilic, while the others were psychrotolerant. The Penicillium isolates were able to decolorize between 60 and 82% of IC. The isolates identified as Pseudogymnoascus showed the best detoxification capacity, with results varying from 49 to 74%. The consortium using only Antarctic ascomycetes (C1) showed 45% of decolorization, while the consortia with the addition of basidiomycetes (C1 + Peniophora and C1 + Pholiota) showed 40% and 50%, respectively. The consortia C1 with the addition of the basidiomycetes presented a lower toxicity after the treatments. In addition, a higher fungal biomass was produced in the presence of dye when compared with the experiment without the dye, which can be indicative of dye metabolization. The results highlight the potential of marine-derived Antarctic fungi in the process of textile dye degradation. The findings encourage further studies to elucidate the degradation and detoxification pathways of the dye IC by these fungal isolates.
RESUMEN
Antarctica is the coldest, windiest, and driest continent on Earth. In this sense, microorganisms that inhabit Antarctica environments have to be adapted to harsh conditions. Fungal strains affiliated with Ascomycota and Basidiomycota phyla have been recovered from terrestrial and marine Antarctic samples. They have been used for the bioprospecting of molecules, such as enzymes. Many reports have shown that these microorganisms produce cold-adapted enzymes at low or mild temperatures, including hydrolases (e.g. α-amylase, cellulase, chitinase, glucosidase, invertase, lipase, pectinase, phytase, protease, subtilase, tannase, and xylanase) and oxidoreductases (laccase and superoxide dismutase). Most of these enzymes are extracellular and their production in the laboratory has been carried out mainly under submerged culture conditions. Several studies showed that the cold-adapted enzymes exhibit a wide range in optimal pH (1.0-9.0) and temperature (10.0-70.0 °C). A myriad of methods have been applied for cold-adapted enzyme purification, resulting in purification factors and yields ranging from 1.70 to 1568.00-fold and 0.60 to 86.20%, respectively. Additionally, some fungal cold-adapted enzymes have been cloned and expressed in host organisms. Considering the enzyme-producing ability of microorganisms and the properties of cold-adapted enzymes, fungi recovered from Antarctic environments could be a prolific genetic resource for biotechnological processes (industrial and environmental) carried out at low or mild temperatures.