The purpose of this project is to investigate the use of proteins derived from bacterial biofilms as a new class of biopolymers for bioplastics production. There is an urgent need for alternatives to conventional plastics, whose manufacture is projected to increase, despite its significant contributions to global greenhouse gas emissions, and the environmental damage caused by its lack of biodegradability. Although a few biodegradable bioplastics exist, they lack the required physical properties to be suitable as replacements for most conventional plastics because they are made from a limited set of naturally occurring biopolymers. An attractive solution leverages recent advances in the field of synthetic biology to create entirely new biopolymers using engineered microbes. With a previous NSF-funded grant, the investigators developed a method to produce customizable protein polymers using engineered non-pathogenic E. coli. This technology enables the molecular structure of the protein polymers to be tailored to exhibit a desired set of properties, analogous to the way that synthetic chemistry can be used to tailor the structures of conventional polymers. For this project, they will further investigate the use of this platform for the production of bioplastics with enhanced material properties. Their approach will involve three aims: 1) engineering the structures of the protein polymers themselves, in order to make them tougher; 2) engineering the microbes that produce the protein polymers to maximize the amount that they produce; and, 3) fabricating bioplastics from the microbial biomass and characterizing their properties. The results from this work will help push the boundaries of national biomanufacturing capabilities, helping shift them toward more sustainable paradigms that will address the imminent challenges of climate change and plastic pollution. The technical research plan is integrated with a plan to introduce emerging topics related to biomanufacturing in coursework targeted toward university students and enable them to advance the engineering of biological systems with hands-on training and creative problem solving.

Technical Abstract

This proposal describes an integrated research and teaching effort that will push the frontiers of biomaterials and biomanufacturing technologies and encompass the training of science and engineering students at multiple skill levels. The proposed research addresses an urgent need for biodegradable bioplastics with enhanced material properties. Conventional plastics are a major source of pollution in our waterways and landfills, and their manufacture contributes significantly to global greenhouse gas emissions. Microbially derived biodegradable bioplastics are an attractive way to address these problems because they are amenable to scaled-up production via fermentation and can rely on renewable feedstocks. However, existing methods for making microbially derived bioplastics rely exclusively on a limited set of naturally occurring biopolymers that exhibit sub-optimal material properties and require cumbersome purification and downstream processing in order to be functional. This project investigates the use of engineered microbes capable of producing protein polymers, whose structure can be tuned through genetic engineering, as a means for producing biodegradable bioplastics with enhanced material properties. In a manner that is analogous to the use of synthetic chemistry to create petroleum-derived polymers with structures highly tailored for specific applications, this project will use synthetic biology to create new biopolymers with tunable properties. The project aims focus on investigating complementary aspects of this new biomanufacturing approach: 1) engineering recombinant protein fibers produced by E. coli to exhibit increased mechanical robustness, 2) engineering the E. coli chassis to maximize the production of these protein fibers; and, 3) developing protocols that make use of whole microbial biomass in order to streamline the bioplastic fabrication process in a manner that is suitable for scaled-up manufacturing. The work will advance fundamental research in protein engineering, metabolic engineering, and biomaterials science to advance its aims. The proposal will also incorporate foundational aspects of biomaterials and biomanufacturing theory and practice into new coursework to be developed at Northeastern University (NEU), and the re-establishment of an iGEM team at NEU.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

National Science Foundation (NSF)
Division of Materials Research (DMR)
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Steve Smith
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Northeastern University
United States
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