TABLE 4.
Enumeration of SRB in an activated-sludge enrichment culture by using synthetic medium (API-RST medium) and sludge medium
| Medium | Detection method | MPN · ml−1 on:
|
||||
|---|---|---|---|---|---|---|
| Day 1 | Day 4 | Day 8 | Day 14 | Day 34 | ||
| Sludge medium | Tracera | 23.1 (a,x)c | 4.1 × 105 (a) | 1.3 × 107 (a) | 1.5 × 107 (a) | 1.5 × 107 (a) |
| API-RST medium | Blackeningb | 2.3 × 104 (b) | 4.3 × 104 (a) | 4.3 × 104 (b) | 4.3 × 104 (b) | 4.3 × 104 (b) |
| Tracer | 2 (x) | 9.2 × 103 (x) | 2.3 × 104 (x) | 2.3 × 104 (x) | 2.3 × 104 (x) | |
a
Positive tubes were detected by the T-MPN method, and the detection limit was 0.1% TRIS.
b
Positive tubes were visually detected by the N-MPN method, i.e., formation of FeS.
c
MPN values in the same column followed by the same letter are not significantly different as determined by the Student t test (P > 0.05). For comparisons of the T-MPN method with sludge medium and the N-MPN method with API-RST medium the letters a and b are used. For comparisons of the T-MPN method with sludge medium and the T-MPN method with API-RST medium the letter x is used.