Environmentally Friendly Production of D(−) Lactic Acid by Sporolactobacillus nakayamae: Investigation of Fermentation Parameters and Fed-Batch Strategies
Table 2
RSM design with real values and experimental results for lactic acid production, productivity, yield, and residual sugar concentration.
Run
Experimental factors
Response variable
Crystallized sugar (g/L)
Yeast extract (g/L)
Salt solution (mL/L)
Lactic acid
Productivity
Residual sugar
g/L
g/Lh
g/g
g/L
1
80.0
15.0
3.0
65.13
1.36
0.81
0
2
160.0
15.0
3.0
59.02
1.23
0.75
81.41
3
80.0
55.0
3.0
61.32
1.28
0.97
17.00
4
160.0
55.0
3.0
58.36
1.22
0.88
93.34
5
80.0
15.0
9.0
26.64
0.56
0.97
52.44
6
160.0
15.0
9.0
62.84
1.31
0.84
85.00
7
80.0
55.0
9.0
65.59
1.37
0.99
14.03
8
160.0
55.0
9.0
59.51
1.24
0.82
87.35
9
120.0
35.0
0.9
71.01
1.48
0.98
47.20
10
120.0
35.0
11.0
88.24
1.84
0.93
25.49
11
120.0
1.40
6.0
44.10
0.92
0.98
74.86
12
120.0
68.5
6.0
53.53
1.12
0.99
65.84
13
52.8
35.0
6.0
50.86
1.06
0.96
0.00
14
187.2
35.0
6.0
70.31
1.46
0.77
96.34
15
120.0
35.0
6.0
87.98
1.83
0.98
30.64
16
120.0
35.0
6.0
81.85
1.71
0.94
33.34
17
120.0
35.0
6.0
85.33
1.78
0.89
24.35
= crystallized sugar; = yeast extract; = salt solution. Culture conditions: 35°C, initial pH at 6.0 neutralized by 5% CaCO3, stationary fermentation, and 10% inoculum. Fermentation was conducted for 48 hours.
