PhD Oral Defense: Molecular characteristics of cold adaptation and subzero growth in polar microorganisms
PhD Oral Defense of Isabelle Raymond-Bouchard, Natural Resource Sciences.
What is the cold limit of life? How do microbes survive and grow in cold subzero environments? Most of the earth鈥檚 ecosystems exist in permanently cold environments where the mean temperature never rises above 15掳C. Permafrost, soil that has been frozen for more than two consecutive year, accounts for 27% of all soil ecosystems on earth. These environments host diverse, living microbial communities. However, our understanding of microbial life in these habitats, their growth, activities, and adaptations, remains limited. Polar habitats serve as some of the best terrestrial analogues to Mars, Europa, and Enceladus and can provide important insights into the potential for subzero life and the cold limits of life both here on Earth and in our Universe. There is also significant interest in the potential discovery of novel antimicrobial compounds from polar microbes and the biotechnological applications of cold-active enzymes. Given the overall lack of research focusing on microbes isolated from permafrost and permafrost-affected soils, the goal of the research in this thesis was to characterize cold growth, especially subzero growth, and cold adaptive properties of subzero growing microorganisms isolated from permafrost environments.