SUPERVISOR: NUMBER OF PAGES: Characteristics and Applications

Elastin-like polypeptides (ELP) are artificially designed protein biopolymers that can be produced by living organisms. These proteins have the unique ability to undergo reversible inverse phase transition, in response to changes in temperature and/or addition of chaotropic salts. Below the transition temperature (T1) , ELP is soluble in water. Increasing the temperature above Ti, ELP coacervates into an aqeous ELP-rich phase. In this thesis, this unique feature of ELP was used in for recombinant protein purification and for the formation of aqueous multiple-phase systems. For protein purification, ELP was fused with an intein and a model protein (thioredoxin), to demonstrate a simple and inexpensive approach for recombinant protein purification. The ELP tags replace the chromatographic media and the intein replaces the use of the protease in conventional methods. Using ELP tags was found to be consistent with large-scale recombinant protein production/purification by purifying an ELP tagged protein using a stirred cell equipped with a microfiltration membrane. When the temperature and/or salt concer.tration is increased for mixtures containing free ELP an