TABLE 1.
Population densities of bacteria and PHBV-degrading denitrifiers in activated sludge
| Sludge sample | Total counta (109 cells ml−1) | Total plate count (108 CFU ml−1)b | No. of PHBV-degrading denitrifiers
|
|
|---|---|---|---|---|
| CFU ml−1b | MPN ml−1 | |||
| NS1 | 6.9 ± 0.1 | ND | 4.9 ± 3.1 × 104 | ND |
| NS2 | 6.1 ± 0.3 | 3.1 ± 0.4 (2.3 ± 0.8) | 2.5 ± 1.4 × 105 (2.3 ± 1.0 × 105) | 1.2 × 108 |
| OS1 | 5.2 ± 0.5 | 1.3 ± 0.4 | 2.2 ± 1.4 × 104 | 1.0 × 107 |
| OS2 | 4.2 ± 0.3 | ND | 1.9 ± 1.3 × 103 | 9.0 × 106 |
| OS3 | 5.6 ± 0.1 | ND | 3.2 ± 2.0 × 103 | 1.1 × 107 |
| TS | 5.3 ± 0.5 | 0.94 ± 0.31 (1.0 ± 0.1) | 1.1 ± 0.2 × 103 (1.4 ± 0.5 × 103) | 7.3 × 106 |
a
Direct total count by EtBr staining. The average values and standard deviations from two different determinations are shown.
b
Average values and standard deviations for triplicate plates are shown. The figures in parentheses show the data obtained at 20 to 22°C for incubation. ND, not determined.