Fig. 1

Schematic diagram of the experimental feeding campaign. Progress of the organic loading rate (OLR) over time for the cautiously fed reactor (CR, a) and the test reactors (R1–R3, b); OLR: organic loading rate (bars) in kg VS m⁻³ d⁻¹; P0 (beginning of the monitoring), P1 (early OLR increase), P2 (late OLR increase), P3 (early acidosis), P4 (late acidosis), and P5 (recovery) are the sampling periods chosen for microbial community analyses