A carbon conserving biosynthetic pathway for the microbial production of fatty acids from glycerol rich waste streams

The production of industrial chemicals using microbes and renewable bio-based feedstocks is advantageous for many reasons. Yet, when microbes use bio-based feedstocks (sugars, glycerol, or other feedstocks) to make more reduced chemicals, deoxygenation most often occurs via the loss of ~33% of the carbon that is present in the sugar as carbon dioxide (CO2), limiting the maximum achievable theoretical yields to ≤67%. As bio-based feedstocks are generally the most expensive component of a bioprocess (typically ~60% total costs), the carbon lost as CO2 amounts to ~20% of the total costs, precluding profitability for many bio-based endeavors. ZymoChem is developing a two-part solution to this problem: (1) developing a new carbon conserving (C2) technology to avoid CO2 production when microbes convert bio- based feedstocks into chemicals. Zymochem’s novel C2 technology is a collection of biosynthetic pathways for making chemicals without losing the feedstock carbon as CO2, in turn increasing theoretical yields up to 50% and creating an opportunity to significantly reduce overall production costs, thus providing an opportunity to supplant their petroleum-based counterparts. (2) Microbes with Zymochem’s C2 technology will utilize glycerol-rich waste streams – which are a byproduct of the bio-ethanol, bio-diesel and oleochemical industries – as the bio-based feedstock. This is particularly attractive since the glycerol-rich waste stream is low-value and reduced in nature (compared to glucose), which lends to lower feedstock costs and higher yields, respectively, during production of industrial chemicals. For this project, Zymochem will develop a novel C2 biosynthetic pathway that is suitable for the conversion of glycerol-rich waste streams to a variety of short-chain fatty acids (SCFAs). SCFAs have a global market of ~$400 million/yr with applications in the cosmetics, coatings, emulsifiers, pharmaceuticals, and flavor industries. In particular, for this SBIR Phase I project, Zymochem will focus on demonstrating successful in vivo production of multiple SCFAs via our proposed C2 pathway and starting from crude glycerol that is generated from a bio-diesel refinery. The work plan for this project will involve (1) biochemical validation of enzymes catalyzing the individual steps in the proposed C2 biosynthetic pathway, and (2) the in vivo production of SCFAs. The proposed project, if successfully commercialized, will enable the upgrading of carbon-rich waste streams to fatty acids in a cost-competitive manner. This will help increase revenues for existing bio-ethanol, bio-diesel and oleochemical plants as well as create new jobs in an environmentally sustainable and socially beneficial way, altogether reducing our reliance on petroleum-derived products. Development of sustainable, cost-competitive, and environmentally friendly microbial processes for the bio-based synthesis of fatty acids from glycerol-rich waste streams.