Mapping the intracellular metabolome of yeast biocapsules – Spherical structures of yeast attached to fungal pellets

Co-culture conditions are beneficial for study due to the advances which arise from symbiotic interactions and which cannot be replicated under pure culture conditions. Here, the focus is on the connection between two fungi – a yeast, Saccharomyces cerevisiae, and a filamentous fungus, Penicillium chrysogenum – in a yeast immobilization system termed’ yeast biocapsules’, where the yeast and filamentous fungus are strongly attached to one another, forming spherical structures. This co-culture condition hinders filamentous fungal biomass growth, while immobilization of yeast cells continues to increase. The effect of the co-culture condition on endometabolites or intracellular metabolites were tracked during the beginning and end of the yeast biocapsule formation period, and metabolites analyzed by Gas Chromatography-Mass Spectrometry Detector (GC-MSD). Distinct metabolite profiles were found between single culture conditions, involving each organism separately, and with the co-culture condition, where there were differences in 54 endometabolites. Specifically, co-culture condition compounds such as fructose, glycolic acid and glyceric acid were present in higher concentrations at the end of biocapsule formation. These results shed light on the mechanisms and biochemical impact of the interaction between the yeast and filamentous fungus and serve as a basis to apply and further develop yeast biocapsules as a new biotechnological tool with benefits for industry.