Diversification of rhamnolipids/glycolipids in heterologous lipogenic yeast hosts using synthetic biology

点击翻译按钮获取中文摘要

Glycolipids (GLs) are produced by diverse organisms, particularly by yeasts and bacteria. The most prominent GLs are rhamnolipids (RLs) that exist in a diversity of RL congeners and homologs. Although their exact physiological functions are unknown, RLs are thought to be produced as defense or survival mechanisms in response to unfavorable environmental conditions. RLs are considered virulence factors of pathogenic microorganisms like Pseudomonas aeruginosa as they help in the colonization of biotic surfaces of humans and plants. Nonetheless, RLs have interesting antimicrobial, antiparasitic, anticancer, immunomodulatory, anti-adherent as well as surface activities allowing them to find several medical, agricultural, environmental, and industrial applications. It is noteworthy that these activities are vary with variations in RL structures creating thus a diversity of biological and physical activities. This richness in biological and physical activities incited the search for new RLs with potentially novel or more interesting activities. Nonetheless, the discovery of new RLs has slowed down drastically in the last decades because it relied on classical screening of new RL producers isolated from environmental samples. This resulted in the redundant identifications of the same RL-producers that are producing the same RLs molecules. Another problem facing RLs commercialization is their costly production arising mainly from the pathogenic nature of their best producers, like P. aeruginosa which is an opportunistic human pathogen. Such pathogenic nature of RL-producers requires costly biocontainment measures which adds to the net cost of RLs. Under the goal to overproduce structurally diverse RLs in non-pathogenic microbial hosts, we set our short-term objective for program to develop proof-of-concept strategies for the genome-mining based heterologous production of diverse RLs in the non-pathogenic lipogenic yeast host, Yarrowia lipolytica. This involves the design of synthetic metabolic circuits biosynthesizing RLs, building and integrating genetic constructs into Yarrowia lipolytica, and finally testing and identification of produced RLs. This design-build-test synthetic biology cycles will be iteratively repeated until the desired RL congener or homolog is produced. In subsequent discovery grants, we will use these strategies to overproduce interesting RL congener or homologs at satisfactory yields and at low cost. This research program will ultimately result in the low-cost production of a diversity of designer RL molecules associated with interesting biological and physical activities that are useful for many therapeutic, environmental, and industrial applications. It will also result in the production of several original research articles, filing of patents and training of highly qualified professionals at undergraduate and graduate levels who will competently contribute to the rising chemical synthetic biology domain in Canada.