Bioprocess Engineering Strategies for the Overproduction of Surface-Expressed Protein in Escherichia coli: A Review.

The use of whole cells represents a modern approach to enzymatic bioconversion for the production of various compounds, particularly pharmaceuticals. In recent decades, the use of wild strains as whole-cell biocatalysts has faced limitations due to challenges such as the lack of control over enzyme production and activity, as well as inefficiencies in enzyme production. As a result, recombinant cells are often employed. Among these, Escherichia coli is the most widely preferred bacterial host for producing recombinant proteins, thanks to its rapid growth, well-developed molecular manipulation tools, the ability to achieve high cell density using cost-effective culture components, and desirable genetic stability. The surface expression of enzymes is one of the most appropriate ways to increase the biotransformation efficiency by recombinant E. coli and reduce overall production costs due to the elimination of the need to purify enzymes and perform the enzyme conversion process in the presence of the pure substrate dissolved in the buffer. This article provides a thorough review of the various factors that influence the production of recombinant surface proteins. It examines aspects that affect biomass growth and methods to enhance protein expression. Additionally, recent research achievements in increasing the production of surface proteins are highlighted, along with promising insights that could pave the way for more sustainable and efficient approaches to producing surface-expressed proteins.