One of the grand challenges of engineering in the 21st century is to provide sustainable and economically-viable commodity products while easing the pressure of population increase, global climate change, and limited natural resources. One plausible approach is to utilize renewable feedstocks that can accommodate these many criteria in long-term adaption and mitigation strategies. Towards this end, microalgae can efficiently convert sunlight and carbon dioxide into high-value products such as biofuels, nutritional supplements, and therapeutic agents. However, the global cellular metabolic processes underlying biofuel and sustainable chemical production from microalgae are not well understood. This project will develop fundamental and applied engineering tools and metrics to better understand how photosynthetic organisms can be exploited to produce high-value products with applications in energy, health, and food industries. The theme of sustainable fuel and chemical production through microalgae-based processes has compelling broad societal impacts, and these topics will be communicated through academic and civic engagement activities that are integrated with the proposed research.
In microalgae, several complex and linked internal mechanisms dictate hydrocarbon biosynthesis, degradation, and, ultimately, the prospect for their accumulation. In fact, preliminary data suggests stress conditions such as nutrient deprivation in microalgae not only trigger lipid and terpenoid biosynthesis but also up-regulate several enzymes responsible for lipid degradation in lysosomes and peroxisomes. The relationship between the expression and interaction of anabolic and catabolic reactions will be investigated with the goal of maximizing hydrocarbon formation that will extend the current understanding of hydrocarbon biosynthesis in microalgae. More specifically, in order to maximize carbon dioxide fixation efficiency and lipid and terpenoid accumulation, a comprehensive experimental and theoretical approach will be employed to understand basic metabolism and improve final metabolite production metrics in non-model oleaginous microalgae. In this work, the microalga Neochloris oleoabundans will be grown under varying nitrogen and phosphorous nutrient levels, and sampled in time-series for transcriptomic and metabolomic analyses designed to characterize and optimize lipid and terpenoid formation. Steady state and dynamic stoichiometric metabolic modeling will be used to determine and predict systems-level responses to critical substrate uptake rates and stress-induced anabolic and catabolic gene activity as they pertain to maximized lipid and terpenoid accumulation. In parallel, a mutagenesis and high-resolution screening design will be applied to further improve non-model microalgae production metrics and, more importantly, provide a comparative basis across all three aims for intracellular metabolism representative of improved hydrocarbon production.
