Cold-Adapted Yeasts in Deep-Sea Environments

Abstract

Deep sea, the world’s largest cold environment, is an environment of extreme conditions, such as high hydrostatic pressure and low nutrient availability, and has an average water temperature between −1 and 4 °C in most areas of deep sea. Living organisms in deep sea are considered to be adapted to cold environments. Yeast diversity commonly found in deep sea is represented by Rhodosporidium spp., Rhodotorula spp., Candida spp., Cryptococcus spp., Pichia spp., Sporobolomyces spp., and Trichosporon spp. This representation of yeasts is similar to yeasts found in other cold environments. Only psychrotolerant yeasts have been reported from deep-sea environments to date. However, the majority of yeasts isolated from deep-sea environments show better growth in deep-sea simulated conditions, such as 3 °C/40 MPa, than yeasts isolated from terrestrial environments. In comparison with prokaryotic microorganisms, yeasts in deep-sea environments are relatively underexplored, with few studies carried out on their physiology. Although the true yeast diversity and their ecology in deep-sea environments remains unclear, the intention of this chapter is to discuss current knowledge on deep-sea yeast diversity and their physiological characteristics and adaptation mechanisms to cold and high pressure in the model yeast Saccharomyces cerevisiae.