(228ae) Combinatorial Engineering Yarrowia Lipolytica As a Platform for Production of Long Chain Omega - Hydroxy Fatty Acids from Renewable Feedstock

Long chain Ï?-hydroxy fatty acids (LCHFA-C16 &18) are among the most important industrially useful fatty acid derivatives. Two functional groups of â??OH and â??COOH on terminal sides provide the longest carbon chain as the monomer as well as high reactivity. These oleochemicals as building blocks or intermediates have special properties including higher viscosity, resistance and biocompatibility, as compared to ordinary fatty acids. They are used for production of surfactants, hot-melt adhesives, powder coatings, corrosion inhibitors, lubricants, plasticizers and greases in chemical industries, and for production of nylons, polyamides and polyesters in bioplastic industries. These di-functional specialty chemicals are advancing innovation in the plastics and coatings industry. They enable creation of novel polymers with superior properties in terms of hydrolytic performance, toughness and flexibility. Furthermore, their wide range of applications as antibacterial, antifungal and anticancer ingredients as well as additive and fragrance precursors in pharmaceuticals, food and cosmetic industries underline the need for establishment of a safe platform for their sustainable production from renewable feedstock. Commercial production of LCHFA is limited due to the lack of cheap, practical, and environment-friendly routes for their synthesis. The chemical synthetic pathways for LCHFA suffer from various disadvantages such as poor selectivity, shortage of selective cheap catalysts, generation of various byproducts and harsh reaction conditions. Additionally, chemical and biological based approaches for degradation of crude/plant oil to these building blocks is mainly dependent on usage of non-renewable feedstock that are more costly than sugar based feedstock. The combination of system and synthetic biology can serve sustainable production of LCHFAs.
Biological based approaches mainly rely on application of cytochrome P450 monooxygenase system. This system performs excellent chemistry in white biotechnology and often serves reactions for valuable molecules such as fine chemicals and pharmaceuticals. Cytochrome P450s systems comprise a large family of enzymes that are predominantly active toward hydroxylation of fatty acids or similar structures. These enzymes can be found in a variety of microorganisms. In microbial consortium, the hydroxylation activity of yeast cytochrome P450 system toward long chain fatty acids is higher than bacterial platform. This study harnesses native lipogenesis capability of Y. lipolytica as a safe oleaginous yeast cell factory platform for biosynthesis of the long chain fatty acids.
Y. lipolytica is an industrially important microorganism. This GRAS organism has strong capability for accumulation and degradation of lipid and lipid precursors. It can utilize a wide variety of carbon sources including sugars from pretreated cellulosic biomass. It is also versatile for P450-catalyzed biotransformation of hydrophobic compounds. This platform has been studied before for biodegradation of oil to long chain dicarboxylic acids. To the best of our knowledge, de novo production of long chain Ï?-hydroxy fatty acid from simple sugar has not been reported before.
We have developed and screened several mutant strains as well as heterologous and homologous fatty acid oxidizing expression systems. Our previous successful demonstration of long chain dicarboxylic acid production from glucose served as inspiring point for further genetic modification to produce sugar based long chain Ï?-hydroxy fatty acids. We obtained minimum LCHFAs titer of 220 mg/L through engineering fatty acid metabolism and oxidation pathways. Subsequently we conducted optimization at a gene level and a process scale. A novel pathway engineering approach of this study was used for sustainable production of LCHFAs of higher selectivity and safe origin, and for increase of yield. The safe status of our platform overvalues the resultant monomers in order to be used in food and pharmaceutical industries. Last but not least, this biological process can help with reduction of green-house gas (GHG) emission associated with petroleum dependent approach for the monomer production.