042 | Functional screening of polar lake fungal isolates reveals region-specific hydrolytic signatures

Aurora Lo Bue¹, Alessandro Ciro Rappazzo², Filomena De Leo¹, Angelina Lo Giudice², Maurizio Azzaro², Maria Papale² | ¹University of Messina; ²Institute of Polar Sciences, National Research Council CNR-ISP, Italy.

Abstract

Cold-lake microorganisms sustain key ecosystem functions in polar freshwater environments, where low temperatures slow abiotic processes and make extracellular enzymes central to carbon and nutrient cycling. By producing cold-active hydrolases, microbial communities depolymerize complex organic matter (polysaccharides, proteins, lipids and chitin-like compounds), controlling the supply of readily available substrates that fuel microbial food webs and influence organic-matter retention versus remineralization. From a biotechnological perspective, cold-adapted microorganisms are valuable sources of enzymes that work efficiently at low temperatures, enabling energy-saving processes and preserving thermolabile compounds. Within this framework, we conducted an initial functional screening of culturable fungi isolates obtained from water and sediment samples collected across 12 coastal lakes: five in the Arctic (Svalbard Islands) and seven along the Antarctic Peninsula coast (King George's Island and Deception Island). We analysed 91 isolates in total (71 Arctic; 20 Antarctic) and screened them for hydrolysis of carboxymethylcellulose, starch, casein, tributyrin, pectin, xylan, and chitin to identify priority candidates and region-specific functional patterns for subsequent quantitative validation at low temperature.
Acknowledgment: PNRA project “Microbial response to human Pollutants in polAr lakeS” -MicroPolArS (PNRA 18_00194).