Before revision:  We show that confinement within polymersomes leads to a significant improvement in protein stability against thermal denaturation up to 95degC at neutral pH, with little or no evidence of unfolding or reduced enzymatic activity.
After revision:  We show that confinement within polymersomes core corresponds to a liquid-liquid phase transition with the protein/water within lumen interacting very differently than in bulk. We show this effect leads to considerable structural changes on the proteins with evidence suggesting non-alpha helical conformations. Most importantly both aspects lead to a significant improvement in protein stability against thermal denaturation up to 95degC at neutral pH, with little or no evidence of unfolding or reduced enzymatic activity.