Project
Model-based production of tailor-made microbial oils
Consumption of plant-based oils, especially palm oil, is increasing at an alarming rate. However, this increasing demand has drastic effects on the ecosystem. Replacing palm oil with oils produced by oleaginous yeasts through the conversion of sustainable feedstocks is a promising alternative. This replacement is strongly dependent on lipid accumulation capacity of oleaginous yeasts. This project aims to establish two oleaginous yeasts as a sustainable and tailor-made fatty acid production platform by deploying iterative Design-Build-Test-Learn approach to that intertwines different approaches.
Background
The use of plant-derived oils, especially palm oil, is increasing at an alarming rate. This is happening in part as a replacement for fossil foils, but mostly as they are cheap sources of many useful components. The oils and fatty acids derived from palm trees are used in food, feed, chemical, personal care, and cosmetic products for health benefits, sensorial reasons (texture, flavor), to extend shelf-life, and as surfactants or emulsifiers. As a result, palm tree groves are rapidly replacing the original tropical forests, and other original and traditional vegetation in many Asian, South American, and African countries. This replacement is not only threatening the local ecosystem but is also having a major effect on the local livelihoods, as it causes deforestation and contributes to climate change. To that end, developing a sustainable alternative to fatty acids and oils is urgent and of utmost interest.
Oil-producing yeasts, referred to as oleaginous yeasts, have strong potential as sustainable alternatives for lipid production in various industrial applications. For sustainable production of oil, two of the promising oleaginous yeast was selected. Although selected microorganisms are able to accumulate lipids up to 40 % of their biomass in nitrogen limiting cultivation medium, the natural capacity of these yeasts is not sufficient to develop an economically feasible production process.
Current design strategies for developing cell factories are sequential and present a clear division between strain design (genetic and metabolic engineering) and bioprocess optimization (media composition and bioreactor operation). This strategy ignores the relations between pathway, metabolism, and culture conditions which might lead to delivering suboptimal production strains. On the other hand, DBTL cycles efficiently execute the scientific method based on hypothesis testing and have been shown to speed up the process of pathway optimization but they are rarely combined with reactor design.
Project description
In order to further establish Cutaneotrichosporon oleaginosus and Yarrowia lipolytica as tailor-made microbial oil producers, the analysis will be performed on the constrained-based genome-scale metabolic models. Transcriptional landscape by contrasting different fatty acid production profiles will be investigated. The findings from these steps will be experimentally validated through engineering these oleaginous yeasts. Finally, these transformants will be characterized and the acquired information will be integrated into the design part.
Results
The optimum C/N ratio and temperature for C. oleaginosus and Y. lipolytica was provided by RSM. Furthermore, we systematically analyzed the variation in fatty acids composition at different C/N ratio and temperature and proved that changing the these parameters steer the composition.