D-Lactic acid fermentation performance and the enzyme activity of a novel bacterium Terrilactibacillus laevilacticus SK5–6

Table 1 Comparison of lactic acid production performance by the catalase-positive T. laevilacticus SK5–6 and the catalase-negative S. laevilacticus 0361^T

Strain	Fermentation time (h)	Cell biomass (OD600)	Lactic acid production performance					Remaining glucose (g/L)	pH
Strain	Fermentation time (h)	Cell biomass (OD600)	Lactate conc. (g/L)	Lactate yield (Y_p/s)^c	Lactate to cell ratio (Y_p/x)^d	Productivity (g/L h)^e	Optical purity (%ee)	Remaining glucose (g/L)	pH
^aT. laevilacticus SK5–6	0	1.481 ± 0.004	0.00 ± 0.00	0	0	0	100.00	122.15 ± 2.48	6.66 ± 0.01
	12	13.325 ± 0.009	45.40 ± 0.85	0.93	3.48	3.78	100.00	73.25 ± 3.61	5.71 ± 0.01
	24	15.938 ± 0.014	79.25 ± 2.48	0.94	5.07	3.30	100.00	37.65 ± 1.06	5.58 ± 0.03
	36	17.675 ± 0.003	93.05 ± 2.05	0.89	5.35	2.58	99.67	17.20 ± 2.40	5.58 ± 0.03
	48	17.500 ± 0.003	102.50 ± 1.70	0.84	5.96	2.14	99.74	0.00 ± 0.00	5.73 ± 0.04
^bS. laevolacticus 0361^T	0	0.032 ± 0.002	0.00 ± 0.00	0	0	0	100.00	120.65 ± 0.50	6.91 ± 0.01
	12	0.567 ± 0.011	0.00 ± 0.00	0	0	0	DL^f	118.30 ± 0.42	6.50 ± 0.01
	24	1.790 ± 0.005	4.75 ± 0.21	0.78	2.70	0.20	81.10	114.55 ± 2.33	5.82 ± 0.04
	36	8.080 ± 0.007	36.95 ± 4.60	0.74	4.59	1.03	97.73	78.40 ± 0.42	5.44 ± 0.02
	48	9.770 ± 0.006	64.80 ± 1.84	0.95	6.65	1.35	99.24	52.50 ± 2.40	5.39 ± 0.01
	60	9.385 ± 0.008	79.70 ± 0.99	0.90	8.52	1.33	98.79	31.75 ± 2.05	5.33 ± 0.04
	72	9.225 ± 0.013	97.70 ± 0.99	0.95	10.63	1.36	99.09	17.75 ± 0.21	5.32 ± 0.03

^aT. Laevilacticus SK5–6 was precultured under the aerobic condition in the medium containing (per liter) 10 g glucose, 15 g yeast extract, 4 g NH₄Cl, and 5 g CaCO₃ supplemented with minerals and salt solution before transferring into the fermentation medium containing (per liter) 120 g glucose and 80 g CaCO₃ at 50% inoculum size. The fermentation was conducted under the anaerobic condition
^bS. laevolacticus 0361^T was precultured under the anaerobic condition in the medium containing (per liter) 10 g glucose, 10 g yeast extract, 5 g peptone, and 5 g CaCO₃ supplemented with minerals and salt solution before transferring into the fermentation medium containing (per liter) 120 g glucose and 80 g CaCO₃ supplemented with minerals and salt solution at 10% inoculum size. The fermentation was conducted under the anaerobic condition
^cLactate yield represented the cumulative value of the ratio of the amount of lactate produced to the amount of glucose consumed at a time
^dLactate to cell ratio referred to the specific production of lactate per unit of cell biomass at a time
^eLactate productivity was calculated from the volumetric production of lactate at a time
^fDL referred to the presence of racemate of lactate at that time

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