Table 1.
MPN enumeration of NO2– and NO3– production after a 42-day incubation of an agricultural soil sample on ULAC medium (pH 5.5) and UL medium (pH 7.6) amended with 0.75 mM urea.
| dilution | MPN score on1) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| ULAC medium | UL medium | ||||||||||
| 10–2 | + | + | + | + | + | * | * | + | * | * | |
| 10–3 | +2) | – | + | + | + | * | * | * | * | * | |
| 10–4 | – | – | + | + | + | * | * | * | * | * | |
| 10–5 | – | – | – | – | – | * | – | * | * | * | |
| 10–6 | – | – | – | – | – | – | – | – | – | * | |
| MPN3) of AOM (ratio) |
2.8×103
(1) |
1.7×105
(61) |
|||||||||
| MPN of NOB (ratio) |
2.8×103
(140) |
0.02×103
(1) |
|||||||||
1) “+”, NO3– was detected (≥10 μM); “*” NO2– was detected (≥10 μM).
2) This culture was selected as the isolation source of NOB and designated as culture A31.
3) MPN (g wet soil)–1.