High Improvement in Lactic Acid Productivity by New Alkaliphilic Bacterium Using Repeated Batch Fermentation Integrated with Increased Substrate Concentration
Table 5
Lactic acid production by repeated batch fermentation coupled with gradual increase in glucose concentrations from 40 to 100 g L−1 by Enterococcus hirae BoM1-2 at pH 9.0 and 40°C.
Batch Number
Initial glucose (g L−1)
LA conc. (g L−1)
(g g−1)
(g L−1 h−1)
Fermentation time (h)
Max (g L−1 h−1)
1
40
3.10±0.196
39.6±0.2
0.99
2.20
18
3.2
2
40
5.40±0.030
39.8±0.2
1.0
2.49
16
3.7
3
40
7.10±0.016
39.7±0.2
0.99
2.84
14
4.5
4
40
8.80±0.001
39.7±0.1
0.99
3.31
12
4.5
5
40
10.1±0.012
39.9±0.3
1.0
3.99
10
4.8
6
40
11.4±0.013
39.6±0.5
0.99
4.95
8
6.3
7
40
12.3±0.020
39.7±0.2
0.99
6.62
6
7.0
8
40
13.9±0.016
39.6±0.3
0.99
9.90
4
11.5
9
40
14.9±0.0217
39.7±0.3
0.99
13.2
3
13.9
10
40
16.7±0.013
39.9±0.4
1.0
19.9
2
22.7
11
40
17.9±0.019
39.9±0.5
1.0
26.6
1.5
28.2
12
40
20.0±0.114
39.7±0.2
0.99
39.7
1
47.3
13
40
21.2±0.013
39.9±0.2
1.0
39.9
1
49.2
14
60
22.3±0.576
59.7±0.2
1.0
19.9
3
24.5
15
60
23.4±0.032
59.4±0.4
0.99
29.7
2
34.7
16
60
24.7±0.418
59.8±0.3
1.0
29.9
2
36.2
17
80
25.5±0.016
79.5±0.3
0.99
19.9
4
22.6
18
80
26.8±0.131
79.4±0.5
0.99
26.5
3
29.5
19
80
27.4±0.521
79.6±0.3
1.0
26.5
3
31.0
20
100
28.1±0.070
99.1±0.3
0.99
19.8
5
23.4
21
100
28.9±0.340
99.2±0.5
0.99
24.8
4
27.8
22
100
29.6±0.253
99.2±0.3
0.99
24.8
4
28.3
23
100
29.7±0.079
98.8±0.5
0.99
16.5
6
21.5
24
100
29.8±0.435
92.0±0.4
0.99
11.5
8
14.2
OD, maximum optical density. Maximum lactic acid concentration after 30 h. Lactic acid yield. Lactic acid productivity at the end of fermentation time. Maximum lactic acid productivity at indicated time.
