Table 1. Effects of the feeding rate and the concentration of the feeding date juice glucose on the cell growth and lactic acid production.
Feeding rate (mL/h) | Feeding glucose (g/L) | Biomass concentration (g/L) | Final lactic concentration (g/L) | Lactic acid productivity (g/L.h)a | Lactic acid yield (g/g)b | Specific growth rate (μ) (h−1)c |
---|---|---|---|---|---|---|
150 | 62 | 10.4 | 56.9 | 0.80 | 1.4 | 0.100 |
75 | 62 | 11.1 | 75.2 | 1.00 | 1.5 | 0.090 |
33 | 62 | 11.8 | 89.2 | 1.30 | 1.7 | 0.080 |
33 | 62* | 8.3 | 57.8 | 0.80 | 1.3 | 0.076 |
33 | 100 | 9.7 | 79.4 | 1.13 | 1.4 | 0.078 |
22 | 100 | 10.4 | 80.4 | 1.15 | 1.4 | 0.076 |
18 | 100 | 10.3 | 84.9 | 1.21 | 1.5 | 0.075 |
Supplements are the same components as the production medium.
The productivity was calculated using the equation: .
The yield was calculated using the equation: .
The specific growth rate was calculated using the equation: .
Pt: Final lactic acid (g/L). Vt: Final volume of the fermentor (L). V 0: Initial volume of the fermentor (L). P 0: Initial lactic acid (g/L). Sa: Glucose concentration of the feeding date juice solution (g/L). St: Residual glucose concentration (g/L). X 0: Initial biomass concentration (g/L). X: Final biomass (g/L).