Life in extreme environments – beneficial properties of microbes from cold habitats

Cold environments of the Swiss alps and the Arctic, such as glaciers and permafrost soils, are threatened by rising global temperatures and bound to disappear in the future. In spite of the harsh environmental conditions, glaciers and permafrost soils are full of microbial life. However, this microbial life is still poorly researched. Our research focuses on the bioprospecting of Alpine and Polar microorganisms to discover natural products that could be useful for biotechnology or medicine. This is especially relevant now, as these environments are among the most rapidly changing due to climate change. Over the past 20 years we have collected soil and ice samples from a variety of terrestrial cryoenvironments. To bioprospect these ecosystems, we have followed two main approaches. The first involves culturing microbes from these environments and establishing a biobank (cryopreserved microbial strains), which now contains approximately 1230 bacteria and 260 fungi. The second approach involves extracting environmental DNA from the samples to investigate the broader microbial communities present. In both cases, our goal is to reconstruct genomes and apply bioinformatic pipelines to identify genes that may encode bioactive compounds or enzymes of interest—such as those with antimicrobial properties that could help us fight microbial infections and polymer degrading enzymes that might sustain a circular economy for plastic waste. A genomic screen using antiSMASH showed a high diversity of gene clusters encoding secondary metabolites with e.g. antibacterial or antifungal properties in biobank isolates. Plate assays testing select biobank isolates with high genetic potential for antibiotic production such as Pseudomonas and Rhodococcus, showed indeed antifungal properties of these isolates. A further genomic screen using PlasticDB additionally revealed high genetic potential for plastic biodegradation in biobank isolates. Rigorous testing of two isolates using ¹³C-labelled substrate confirmed their ability to biodegrade untreated polyethylene. These two examples of the use of biobank isolates shows that microorganisms of cold environments are a rich resource.