FIG. 3.

CLSM image of cryosectioned granules after FISH, with “Candidatus Accumulibacter phosphatis” in blue, “Candidatus Competibacter phosphatis” in yellow, and all other bacteria in green. (a) Synthetic-1 white granules were imaged on day 98 of reactor operation and were dominated by “Candidatus Accumulibacter phosphatis” with a solid, compact outer-wall structure. (b) Synthetic-1 yellow granules were imaged on day 98 of reactor operation and had a diverse bacterial population, were generally larger, and consisted of numerous compartmentalized microcolony structures. (c) Synthetic-1 off-white granules were imaged on day 168 of reactor operation and appeared as a mixture of the white and yellow granules with both solid outer walls and microcolony structures. (d) Domestic white granules were imaged on day 68 of reactor operation, were dominated by “Candidatus Accumulibacter phosphatis,” and exhibited a solid, compact outer-wall structure similar to that of the Synethic-1 white granules. (e) Domestic yellow granules were imaged on day 68 of reactor operation and exhibited a solid structure with fewer microcolonies and a more diverse bacterial population than the Synthetic-1 yellow granules. All scale bars, 100 μm.