Design of a Molecular Chaperone‐Assisted Protein Folding Bioreactor

Abstract
Escherichia coli molecular chaperone GroEL and co‐chaperone GroES are well known to assist the folding/refolding of a diverse range of substrate proteins. Despite this, there have been relatively few reports of the GroEL/GroES molecular chaperone system being used as a biotechnology tool for protein folding/refolding. In this paper, a solution‐phase protein folding bioreactor is described that involves the complete GroEL/GroES system. The main features of this bioreactor are the use of a stirred‐cell concentrator fitted with a 100 kDa molecular weight cutoff membrane and an attached buffer reservoir. This bioreactor system was used successfully for assisted‐batch refolding of guanidinium chloride (Gu‐HCl) unfolded mitochondrial malate dehydrogenase (mMDH). We believe that protein folding bioreactor systems of this type could have wide potential utility for the folding/refolding of unfolded protein substrates.