The invention provides methods and systems by which enzymes can be modified to improve solubility, catalytic activity, recoverability, and recyclability. The enzyme may be modified with a thermosensitive copolymer to form an enzyme-polymer conjugate that exhibits upper critical solution temperature (UCST) and/or lower critical solution temperature (LCST)-type behavior in an organic solvent, ionic liquid, or other solvent. Methods and systems of the invention facilitate the use of enzymes as biocatalysts in solvents.