Table 3. Denitrifying activities in the biofilm cultures.
| Biofilm cultures | Denitrification rates mM-NOxh−1 flask−1 | Relative activities | Protein concentration mg/vial | Specific denitrification rates mM-NOxh−1 mg-protein−1 | Relative specific activities |
|---|---|---|---|---|---|
| 0%NaCl | 1.28 (0.01) | 0.87 (0.01) | 14.1 (1.2) | 0.0911 (0.0080) | 1.72 (0.15)b |
| 0.5%NaCl | 1.57 (0.02) | 1.06 (0.01) | 22.2 (2.6) | 0.0712 (0.0084) | 1.34 (0.16)ab |
| 1%NaCl | 0.66 (0.01) | 0.45 (0.01) | 18.5 (0.2) | 0.0357 (0.0011) | 0.67 (0.02)cd |
| Ref300N-23C* | 1.47 (0.05) | 1.00 (0.03) | 28.1 (0.4) | 0.0530 (0.0064) | 1.00 (0.12)ad |
| 300N-30C | 1.94 (0.04) | 1.32 (0.03) | 20.5 (0.9) | 0.0946 (0.0027) | 1.79 (0.05)b |
| 900N-23C | 1.95 (0.04) | 1.32 (0.02) | 30.7 (2.9) | 0.0637 (0.0060) | 1.20 (0.11)abd |
| 900N-30C | 2.37 (0.09) | 1.61 (0.06) | 24.5 (2.8) | 0.0979 (0.0130) | 1.85 (0.24)b |
| Ref300N-23C* | 1.42 (0.01) | 1.00 (0.01) | 31.0 (1.8) | 0.0458 (0.0027) | 1.00 (0.06)ad |
| Oxic | 0.18 (0.08) | 0.12 (0.06) | 19.8 (1.1) | 0.0090 (0.0046) | 0.20 (0.10)c |
| 5%NaCl | 0.06 (0.01) | 0.04 (0.01) | 0.38 (0.12) | 0.1660 (0.0322) | 3.63 (0.70)e |
| 2.75–5%NaCl | 2.46 (0.08) | 1.74 (0.06) | 62.7 (3.5) | 0.0394 (0.0032) | 0.86 (0.07)ad |
| 8%NaCl | 0.07 (0.01) | 0.05 (0.01) | 0.84 (0.04) | 0.0845 (0.0071) | 1.84 (0.15)b |
| Ref300N-23C* | 1.89 (0.10) | 1.00 (0.05) | 27.6 (1.5) | 0.0684 (0.0005) | 1.00 (0.01)ad |
| IO | 0.76 (0.03) | 0.40 (0.01) | 11.5 (0.8) | 0.0661 (0.0063) | 0.97 (0.10)ad |
| 200/200N | 0.39 (0.13) | 0.41 (0.01) | nd | nd | nd |
Notes.
Except for the 200/200N biofilm cultures, three sets of cultures assays were performed with the Ref300N-23C biofilm cultures in each set for comparison. Relative activities are to the denitrification rates of the Ref300N-23C biofilm cultures set to one. Protein concentrations reflect the biomass content in vials at the end of the assays. Specific denitrification rates are the denitrification rates divided by protein amount in vials. Relative specific activities are to the specific denitrification rates of the Ref300N-23C biofilm cultures set to one. Significance between the relative specific denitrification rates was determined by one-way ANOVA with Tukey’s Multiple Comparison Test. The relative specific denitrification rates with the same letter are not significantly different. See Table 2 and Material & Methods for nomenclature and culture conditions. Results are average of triplicate biofilm cultures. Values between parentheses: standard deviation. nd: not done.