Recombinant Food Proteins Expressed in E. coli as Complement to Plant Proteins in the Protein Shift

Abstract: Increased awareness regarding nutrition, environmental sustainability, and animal welfare has sparked a trend to shift away from animal proteins. The phenomenon is referred to as the protein shift and has resulted in a higher demand for alternative protein sources. This dissertation aims to study potential opportunities and challenges of using recombinant food proteins expressed in Escherichia coli as a complement to plant proteins and to compare sustainability, cost, functionality, and consumer acceptance. The thesis is based on existing literature and thus takes the form of a critical literature review. Results revealed a series of opportunities and challenges. Plant proteins have a variety of functionalities which creates better opportunities to mimic the characteristics seen in animal products. Novel methods have been discovered that enables the production of large, fibrous plant-based whole cuts. Challenges that remain are mimicking of marbled fat in meat analogs and off-flavors in plant-based milk. The most prominent advantages of recombinant proteins are cost- and time efficiency and that they can be modified to exclude allergenic components. However, several parameters have to be considered when constructing a functioning bio factory which can be difficult. Additional challenges are related to consumer acceptance and legislation. An environmental assessment revealed that recombinant proteins have the potential to lower greenhouse gas emissions, but additional research should be conducted on land use and water footprint. Recombinant food proteins may be able to compete with plant proteins in terms of cost and functionality, but not equally as much in regard to consumer acceptance. The findings suggest that recombinant proteins cannot fully replace plant proteins at the time but could be added as complementing ingredients to achieve certain properties. Future research should investigate how recombinant proteins behave in food matrices and how biofactories can be optimized with respect to organism, strain, vector, promoter and markers.