Contributors: Tank
Counted colonies from the 14 August serial-dilution plates. The 10⁻³ and 10⁻⁴ dilutions were too dense to count across all cultures; only 10⁻⁵ gave countable plates:
| Culture | CFU (10⁻⁵ dilution) |
|---|---|
| 1a — glucose + beta-glucosidase | 607 |
| 1b — glucose + beta-glucosidase | 596 |
| 2a — glucose + CxnA | too dense to count |
| 2b — glucose + CxnA | 832 |
| 3a — cellobiose + CxnA | 185 |
| 3b — cellobiose + CxnA | 191 |
| 4a — cellobiose + beta-glucosidase | 247 |
| 4b — cellobiose + beta-glucosidase | 234 |
2a’s plate showed significantly more colonies than every other dilution and replicate, including its own pair (2b) — this doesn’t fit the pattern and is suspected to be a serial-dilution error rather than a genuine difference between 2a and 2b.
Replicates agree reasonably well within each condition (except 2a), and both cellobiose conditions (3, 4) show clearly lower CFU than both glucose conditions (1, 2) — consistent with the lower OD600 readings from 14 August.