Screening and Partial Purification of Antifreeze Proteins from Polar Microalgae

Abstract

Antifreeze proteins (AFPs) can protect organisms from freezing injury by adsorbing to ice and inhibiting its growth. We screened the antifreeze activity from polar Microalgae and isolated more than 10 microalgal strains showing the activity. The presence of antifreeze activity was observed by nanolitre osmometer. Among them, two microalgal strains, KOPRI ArM0014 and KOPRI AnM0046, were further investigated and their antifreeze proteins were partially purified. The supernatant of culture in log phase were harvested and filtered through Tangential flow filtration (TFF). Then cold finger method which uses ice seed to let antifreeze protein to bind to the surface of an ice, is used to selectively adsorb and extract Antifreeze proteins (AFPs) from culture solutions of two strains. Extracellular Antifreeze proteins(AFPs) were analyzed by SDS-PAGE. The extracted proteins showed antifreeze activity and were subject to further characterization.