Table 1.
A. spinosum concentration (cell·mL−1), mean estimated spherical diameter (ESD) (µm), cellular volume (µm3·mL−1), toxin content (fg·cell−1), and cell and toxin production (cell·day−1 and µg·day−1, respectively) at the dilution rates studied (0.1, 0.15, 0.2, 0.25, 0.3 day−1) in the two bioreactors in series (R1 and R2). Standard deviations were calculated from sequential repeat measurements of each culture and the last columns present the result of the multifactorial ANOVA followed by a Fisher least-significant-difference test to discriminate differences between values within each factor.
| A. spinosum | n | 0.1 day−1 | 0.15 day−1 | 0.2 day−1 | 0.25 day−1 | 0.3 day−1 | Main factors | Interaction | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| R1 | R2 | R1 | R2 | R1 | R2 | R1 | R2 | R1 | R2 | Dilution rate (D) | Reactor (R) | D–R | ||
| Concentration(×103 cell·mL−1) | 9–22 | 174 ± 6 | 164 ± 4 | 193 ± 6 | 214 ± 3 | 194 ± 8 | 214 ± 7 | 190 ± 6 | 221 ± 5 | 187 ± 5 | 220 ± 4 | p ≤ 0.05 | p ≤ 0.05 | p ≤ 0.05 |
| 0.1 < 0.15 = 0.2 = 0.25 = 0.3 | R1 < R2 | |||||||||||||
| Mean ESD(µm) | 9–22 | 9.81 ± 0.09 | 10.1 ± 0.1 | 9.59 ± 0.15 | 9.9 ± 0.2 | 9.6 ± 0.2 | 10.1 ± 0.2 | 9.29 ± 0.09 | 9.93 ± 0.04 | 9.5 ± 0.1 | 10.02 ± 0.05 | p ≤ 0.05 | p ≤ 0.05 | p ≤ 0.05 |
| 0.25 = 0.3 < 0.15 < 0.2 = 0.1 | R1 < R2 | |||||||||||||
| Cellular volume(×107 µm3·mL−1) | 9–22 | 8.8 ± 0.4 | 8.4 ± 0.3 | 9.2 ± 0.4 | 11.1 ± 0.4 | 9.3 ± 0.6 | 12.0 ± 0.7 | 8.2 ± 0.3 | 11.7 ± 0.2 | 8.5 ± 0.1 | 12.0 ± 0.4 | p ≤ 0.05 | p ≤ 0.05 | p ≤ 0.05 |
| 0.1 < 0.25 = 0.3 = 0.15 < 0.2 | R1 < R2 | |||||||||||||
| AZA1 (fg·cell−1) | 3–5 * | 37 ± 5 | 65 ± 8 | 52 ± 6 | 74 ± 4 | 34 ± 12 | 76 ± 14 | 26 ± 2 | 61 ± 3 | 17 ± 1 | 45 ± 3 | p ≤ 0.05 | p ≤ 0.05 | p ≤ 0.05 |
| AZA2 (fg·cell−1) | 3–5 * | 10 ± 1 | 16 ± 1 | 15 ± 1 | 24 ± 2 | 10 ± 2 | 19 ± 2 | 12 ± 2 | 25 ± 2 | 7 ± 1 | 18 ± 2 | |||
| AZA1 + 2 (fg·cell−1) | 3–5 * | 47 ± 6 | 81 ± 9 | 67 ± 3 | 98 ± 5 | 44 ± 13 | 95 ± 16 | 38 ± 2 | 86 ± 3 | 24 ± 1 | 63 ± 5 | 0.3 < 0.25 = 0.1< 0.2 < 0.15 | R1 < R2 | |
| Cell production (×109 cell·day−1) | n/a | 1.74 ± 0.06 | 1.64 ± 0.04 | 2.90 ± 0.09 | 3.21 ± 0.05 | 3.9 ± 0.2 | 4.3 ± 0.1 | 4.8 ± 0.2 | 5.5 ± 0.1 | 5.6 ± 0.2 | 6.6 ± 0.1 | Cell production = Cell concentration × D | ||
| Toxin production AZA1 + 2 (µg·day−1) | n/a | 82 ± 3 | 134 ± 15 | 193 ± 9 | 314 ± 15 | 170 ± 50 | 406 ± 64 | 180 ± 10 | 475 ± 17 | 134 ± 5 | 415 ± 33 | Toxin production = Cell production × [AZA1 + 2] | ||
* Each sample was also injected in triplicate to reduce analytical variability; n/a not applicable.