QUANTITATIVE SINGLE-CELL DETECTION OF POLY(BETA-HYDROXYBUTYRATE) ACCUMULATION IN RHIZOBIUM-MELILOTI BY FLOW-CYTOMETRY

The ability of flow cytometry to detect intracellular accumulation of poly(beta-hydroxybutyrate) (PHB) in individual cells of Rhizobium meli loti was investigated using light scatter parameters. PHB accumulation during stationary phase was shown to form inclusion bodies inside cel ls which were detected by forward angle light scatter (FALS) parameter . A linear relationship was found between FALS intensity and percentag e of PHB (w/w) of cells, demonstrating that flow cytometry allowed a q uantitative analysis of intracellular PHB accumulation. In addition, r esults showed the ability of flow cytometry to quantify heterogeneity of rhizobia population in fermentation according to PHB production and accumulation.