(200f) Let Yeast Fart: Modeling the Spatiotemporal Patterns of Yeast Sulfur Metabolism and Its Applications for CO2 Fixation

Biological process is among the most intricate and complex mystery on Earth. Biochemical engineering aims to utilize the design logic of life processes and apply chemical engineering principles to address environmental, energy, and medicine challenges. Sulfur assimilation pathway is one untapped area for biocatalysis, cellular engineering and material synthesis. We developed a genetically engineered yeast capable of accumulating large amount of hydrogen sulfide. We harnessed the yeast-derived H₂S and synthesized nanoscale quantum dots (CdS, CdSe and ZnS). Embedding the quantum dots on the surface of yeast peroxisome, we achieved efficient photocatalytic fixation of CO₂, the lipid yield was improved 45% and CO₂ emission was reduced by 42%. With simple mathematial models, we unraveled the genetic and metabolic interlay underlying the sulfur assimilation circuitry. Our model replicates the concentric ring patterns of H₂S distributon on agar plate and the oscillatory H₂S patterns in liquid media. Interestingly, our simulation indicates that yeast could rapidly re-incorporate H₂S to complement methionine deficiency, and the onset of expressing H₂S assimilation pathway follows a population-dependent manner. Our approach contributes to the understanding of genetic and metabolic interplay of yeast sulfur metabolism and its applications for CO₂ fixation.