TABLE 2.
Enumeration of iron- and nitrate-reducing bacteria in carbon-amended and -unamended microcosms and homogenized FB094 core sediment
| Inoculum, day | MPN carbon substrate | MPN (cells g−1) ofa:
|
|
|---|---|---|---|
| FeRBb | NRBc | ||
| Glucose microcosms, day 7 | Glucose | 3.2 × 106 (7.0 × 105-1.5 × 107) | 4.5 × 109 (9.5 × 108-2.1 × 1010) |
| Ethanol microcosms, day 7 | Ethanol | 1.0 × 109 (2.2 × 108-4.7 × 109) | 2.5 × 109 (5.5 × 108-1.2 × 1010) |
| Glucose microcosms, day 21 | Glucose | 2.0 × 107 (4.3 × 106-9.5 × 107) | ND |
| Ethanol microcosms, day 21 | Ethanol | 2.0 × 108 (4.3 × 107-9.50 × 108) | 2.0 × 109 (4.3 × 108-9.5 × 109) |
| Unamended microcosms, day 21 | Glucose | 1.2 × 102 (25-5.5 × 102) | 1.0 × 108 (2.2 × 107-4.7 × 108) |
| Ethanol | 1.0 × 104 (2.2 × 103-4.7 × 104) | 4.5 × 107 (9.5 × 106-2.1 × 108) | |
| Homogenized FB094 sediment | Glucose | 2.1 × 103 (4.5 × 102-9.8 × 103) | 4.0 × 106 (8.6 × 105-1.9 × 107) |
| Ethanol | 1.5 × 104 (3.2 × 103-7.0 × 104) | 4.0 × 103 (8.6 × 102-1.9 × 104) | |
a
Values represent abundance in cells g−1 sediment wet weight, determined in three replicate MPN serial dilutions after 3 months of incubation at 30°C. Values in parentheses represent the range of the MPN values within 95% certainty. ND, not determined.
b
MPN estimates for FeRB grown with FeOOH as an electron acceptor.
c
MPN estimates for NRB grown with nitrate as the electron acceptor.