The broader impact/commercial potential of this Small Business Technology Transfer Phase I project will be the development of a new biological route, based on microbial co- cultures, for efficient production of an environmentally friendly (eco-friendly) mixture of biopolymers for revegetation and erosion control applications, with a $375 million potential market. Tackifying polymers (adhesive-like materials) are widely used to stabilize loose soils/mulches and promote revegetation via aggregation and water retention. This project will focus on producing an eco-friendly biopolymer mixture of microbial polyamino acids and polysaccharides that has improved properties compared to conventional tackifiers, providing superior adhesion and water retention. Despite promising potential and market demand for more effective bio-based tackifiers, these microbial biopolymers have never been investigated for use in this application, as current fermentation methods for producing them are not economical. The key innovation in this project entails engineering microbial co-cultures to produce relatively expensive biopolymer precursors in-situ from beet molasses, an inexpensive and renewable feedstock, resulting in dramatic cost reductions. Beyond biopolymer production, the proposed approach of engineering co-cultures for in-situ precursor production (ISPP) is potentially transferrable to many other bioprocesses, and could offer more efficient, cost-effective routes for producing other bio-based fuels and chemicals. The objectives of this Phase I research project are to i) implement, experimentally characterize, and model co-culture prototypes to demonstrate technoeconomic feasibility of biopolymer production with this approach, and ii) validate the performance of these biopolymers in revegetation and erosion control applications. Completion of these objectives will demonstrate proof-of-concept, and represent important technical milestones towards commercializing this technology. The proposed approach of engineering synthetic microbial consortia represents a distinct shift from the conventional paradigm of utilizing single-species monocultures for bioprocessing and offers substantial potential cost-savings through in-situ precursor production and process consolidation. Despite these potential benefits, synthetic microbial consortia for bioprocessing have not been explored in a commercial context due to the level of high technical risk entailed. Building on prior NSF-funded academic research in engineering consortia for cellulosic biofuel production, this project will implement microbial co- cultures capable of producing polyamino acids / polysaccharides through ISPP and perform a preliminary investigation of the interplay between ecological interactions, environmental conditions, and key performance metrics (such as titer, yield, and biopolymer composition). This project will also investigate the novel application of polyamino acids / polysaccharides as bio-tackifiers for revegetation and erosion control, enabled by the potential cost-savings of the proposed co-culture.
