Table I
Mean composition (g/l) of the substrates used as culture media.
| Nutrient | DW medium | CMPW medium | CMPWGP medium |
|---|---|---|---|
| Lactose | 22.62 ± 0.05 | − | − |
| Glucose | − | 101.72 ± 0.17 | 400.00 ± 0.01 |
| Total nitrogen | 0.433 ± 0.02 | 0.540 ± 0.01 | 0.431 ± 0.02 |
| Total phosphorus | 0.227 ± 0.02 | 0.060 ± 0.00 | 3.210 ± 0.06 |
| Proteins | 2.07 ± 0.01 | 3.47 ± 0.03 | 2.75 ± 0.02 |
Fig. 1.
Time course of the culture pH (◊), pH gradient (VpH, ●), and remaining (○), consumed (£), added (∆) and extracted (▲) concentrations of glucose (G), lactose (L), proteins (Pr), total nitrogen (TN), and phosphorus (TP) in the realkalized fed-batch culture I. The data reported are means ± standard deviations of two repeated experiments and three replicate measurements.
Fig. 2.
Time course of the culture pH (◊), pH gradient (VpH, ●), and remaining (○), consumed (£), added (∆) and extracted (▲) concentrations of glucose (G), lactose (L), proteins (Pr), total nitrogen (TN), and phosphorus (TP) in the realkalized fed-batch culture II. The data reported are means ± standard deviations of two repeated experiments and three replicate measurements.
Fig. 3.
Time course of the biomass (X), viable cell counts (VCC), nisin (Nis), lactic acid (LA), acetic acid (AA), and butane-2,3-diol (B) in the realkalized fed-batch cultures I (left side), and II (right side). The data reported are means ± standard deviations of two repeated experiments and three replicate measurements. The solid lines drawn through the experimental data for each variable were obtained according to the empirical model [7].
Table II
Significant values (p < 0.05) for the constants in model [7] for the different dependent variables in the first fed-batch culture.
| Parameter | Biomass | Viable cell counts | Nisin | Lactic acid | Acetic acid | Butane-2,3-diol |
|---|---|---|---|---|---|---|
| A1 | 4.12 ± 0.631 | 1.86 ± 0.084 | 1.13 ± 0.113 | 5.71 ± 0.235 | 1.16 ± 0.003 | 2.75 ± 0.277 |
| A2 | −3.60 ± 0.545 | −1.56 ± 0.072 | 8.67 ± 0.4244 | −4.04 ± 0.225 | −0.70 ± 0.012 | −2.00 ± 0.265 |
| A3 | 0.83 ± 0.116 | 0.41 ± 0.015 | −2.07 ± 0.206 | 0.88 ± 0.054 | 0.12 ± 0.005 | 0.37 ± 0.064 |
| A4 | −1.09 ± 0.383 | −0.15 ± 0.051 | −9.25 ± 1.547 | −0.92 ± 0.040 | −0.46 ± 0.021 | −0.19 ± 0.021 |
| A5 | 0.14 ± 0.062 | 0.03 ± 0.008 | 2.93 ± 0.314 | 0.26 ± 0.019 | 0.15 ± 0.011 | 0.03 ± 0.003 |
| A6 | 0.35 ± 0.168 | NS | 0.74 ± 0.203 | NS | NS | NS |
| R2 | 0.9950 | 0.9948 | 0.9993 | 0.9986 | 0.9949 | 0.9954 |
| RPDM (%) | 3.335 | 0.228 | 1.121 | 3.760 | 1.701 | 5.809 |
| VpHopt | 1.81 | 1.92 | 2.32 | 2.30 | 2.83 | 2.40 |
| pHopt = 7.0 – VpHopt | 5.19 | 5.08 | 4.68 | 4.70 | 4.17 | 4.60 |
| Gopt (g/l) | 1.64 | 2.72 | 1.29 | 1.76 | 1.41 | 2.80 |
Table III
Significant values (p < 0.05) for the constants in model [7] for the different dependent variables in the second fed-batch culture.
| Parameter | Biomass | Viable cell counts | Nisin | Lactic acid | Acetic acid | Butane-2,3-diol |
|---|---|---|---|---|---|---|
| A1 | 0.46 ± 0.043 | 0.58 ± 0.053 | 0.42 ± 0.040 | 10.19 ± 0.405 | 0.41 ± 0.032 | 0.23 ± 0.062 |
| A2 | −3.32 ± 0.351 | −1.75 ± 0.062 | −27.69 ± 1.011 | −8.10 ± 0.621 | −2.19 ± 0.027 | −3.15 ± 0.333 |
| A3 | 0.58 ± 0.059 | 0.45 ± 0.011 | 6.53 ± 0.462 | 1.79 ± 0.109 | 0.44 ± 0.024 | 0.63 ± 0.097 |
| A4 | 0.53 ± 0.038 | 0.26 ± 0.065 | 4.73 ± 0.516 | −0.35 ± 0.017 | 0.42 ± 0.023 | 0.72 ± 0.065 |
| A5 | −0.04 ± 0.005 | −0.01 ± 0.003 | −0.10 ± 0.013 | 0.03 ± 0.006 | −0.02 ± 0.001 | −0.04 ± 0.004 |
| A6 | 0.11 ± 0.006 | NS | NS | NS | NS | NS |
| R2 | 0.9973 | 0.9906 | 0.9950 | 0.9959 | 0.9794 | 0.9856 |
| RPDM (%) | 0.987 | 0.326 | 3.775 | 2.609 | 3.988 | 3.602 |
| VpHopt | 1.82 | 1.96 | 2.12 | 2.26 | 2.47 | 2.49 |
| pHopt = 7.0 – VpHopt | 5.18 | 5.04 | 4.88 | 4.74 | 4.53 | 4.51 |
| Gopt (g/l) | 10.55 | 11.10 | 22.83 | 5.30 | 11.17 | 10.27 |
Table IV
The optimal final culture pH values for different bacteriocins produced by lactic acid bacteria.
| Bacteriocin | Producing strain | Optimum final pH | Culture medium | Reference |
|---|---|---|---|---|
| Mesenterocin 5 | Leuconostoc mesenteroides UL5 | 4.24 to 4.34 | Whey | Daba et al. 1993 |
| Pediocin AcH | Pediococcus acidilactici LB42-923 | 3.70 | TGE broth | Yang and Ray 1994 |
| Nisin | Lactococcus lactis ATCC 11454 | 5.80 | TGE broth | Yang and Ray 1994 |
| Leuconocin Lcm1 | Leuconostoc carnosum Lm1 | 5.00 | TGE broth | Yang and Ray 1994 |
| Sakacin A | Lactobacillus sake LB 706 | 4.50 | TGE broth | Yang and Ray 1994 |
| Nisin | Lactococcus lactis ATCC 7962 | 4.90 | Whey permeate | Flôres and Alegre 2001 |
| Carnocin KZ213 | Carnobacterium piscicola 213 | 4.80 to 5.08 | MRS broth | Khouiti and Simon 2004 |
| Nisin | Lactococcus lactis ATCC 11454 | 4.60 | MRS + milk | Penna et al. 2005 |
| 4.80 | M17 + milk | |||
| Nisin | Lactococcus lactis ATCC 11454 | 4.65 to 4.96 | Whey + YE (5 g/l) | Jozala et al. 2011 |