Time courses of relevant parameters of the defined continuous cultures during the experiment with various sulfate and PCE concentrations in the reservoir medium. Culture conditions: stable condition 1 with 1 mM SO42− plus PCE; stable condition 2 with 2.5 mM SO42− plus PCE; stable condition 3 without SO42− and with PCE; stable condition 4 without SO42− and without PCE; pH 7.1 (±0.1); 34.5°C; dilution rate, 0.02 h−1; electron donor, 2.5 mM fructose. PCE was present at 170 (±20) μM (=100%). PCE was omitted from the reservoir medium at day 32 (as indicated by the arrow). Methanobacterium formicicum was added at day 34. (A) Optical densities (○) and sulfide concentrations (▪) in the liquid. (B) Relative cell numbers in the percentages of Desulfitobacterium frappieri TCE1 (○), Desulfovibrio fructosivorans (▪), and Methanobacterium formicicum (•) (for 100%, see total values in Table 2). (C) Concentrations of fructose (▪) and acetate (○) in the culture liquid during sulfate reduction and/or fermentation by Desulfovibrio fructosivorans. (D) Concentrations of PCE (○), TCE (⧫), and cis-DCE (▪) in the culture liquid.