Intensification of inclusion body processing via surface refolding with chemical extraction

Abstract

In this PhD work, gloshedobin, a kind of thrombin-like enzyme, expressed mainly as inclusion bodies in E. coli, was successfully produced as intact form with significant amount of recovered activity. The contamination of truncated expression products was eliminated by co-expression of a molecular chaperone, ClpB. A folding-like-refolding strategy harnessing unpurified ClpB and DnaK/DnaJ/GrpE bichaperone system was developed using a model protein (heat-denatured malate dehydrogenase) and successfully applied to enhance the column-based refolding of full-length gloshedobin from cell disruptates. Further process intensification for recovery of gloshedobin IBs was achieved by incorporation of PEI-mediated chemical extraction with IMAC protein purification to overcome the inefficiencies associated with the traditionally used IB recovery strategy, such as mechanical cell disruption. This novel process intensification method, together with the approach to reduce the truncated expression products and the folding-like-refolding strategy are thus expected to lead to a more efficient and economically viable processing route for the large-scale production of refolding-recalcitrant IB proteins.