Many microorganisms accumulate high-energy compounds such as triacylglycerols (TAG) and polyphosphate (polyP) in intracellular granules. These compounds provide energy reserves for the cell to survive suboptimal conditions. Additionally, recent findings have suggested that these high-energy granules are not simply for energy storage, but have important cellular roles involved in protein folding, gene expression and signaling, among others. In addition to understanding the functional significance of these energy reserves, identifying mutants or strains with increased accumulation of TAG or polyP is of biotechnological interest due to our current dependence on non-renewable energy and phosphate sources (i.e. fossil fuel and phosphate mining). In this talk, I will present the use of flow cytometry as a high-throughput screen to detect and enrich for cells hyper-accumulating TAG or polyP. I will first talk about the method we have developed for isolating mutants with increased lipid accumulation in model alga Chlamydomonas reinhardtii. In this approach, 50% of the isolated mutants have a reproducible high lipid phenotype. Secondly, I will present ongoing work on wastewater bacterial community screening for polyP hyper-accumulating strains. Initial findings suggest that bacterial species stemming from phylum Firmicutes and alphaproteobacteria may have a larger role in phosphate removal from wastewater than previously expected.
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