Table 1.

Fermentation profiles of B. coagulans derivatives on the path to D(−)-lactic acid production at 50 °C

Strain	Genotype	Culture	Cell	Glucose	Qs*	Product (mM)							Yield †
		pH	Yield	Consumed		Lactate		Pyruvate	Acetate	Succ	Formate	Ethanol	Lactate	Total
				(mM)		L(+)-	D(−)
P4-102B	wild type	5.0	3.0	144.3	5.7	255.6	UD	UD	5.7	0.6	UD	10.5	0.89	1.00
		7.0	7.1	188.6	18.4	336.4	UD	UD	15.9	0.4	UD	4.6	0.89	0.96
QZ4 ‡	Δldh	5.0	1.8	53.8	0.8	UD	1.0	UD	UD	1.0	6.5	20.3	0.01	1.03
		7.0	8.1	226.0	4.3	UD	9.7	UD	42.3	6.7	90.6	224.5	0.02	1.17
QZ5	Δldh Δ alsS	5.0	2.5	32.8	0.5	UD	9.8	4.5	4.6	0.1	25.3	25.6	0.15	0.72
		7.0	5.8	152.5	6.8	UD	12.8	10.1	95.4	2.1	154.6	164.5	0.04	0.94
QZ13	evolved §	5.0	4.3	128.8	2.4	UD	212.4	6.1	2.7	0.6	24.3	23.4	0.82	0.95
		7.0	6.0	162.6	4.0	UD	219.8	9.3	14.8	0.4	66.9	58.1	0.68	0.93
QZ14	evolved §	7.0	ND ¶	265.7	5.4	UD	468.4	1.6	UD	1.3	21.5	28.4	0.88	0.93
QZ15	evolved §	7.0	ND ¶	562.6	17.0	UD	928.2	UD	22.6	8.1	UD	97.5	0.83	0.94
QZ19	evolved §	5.0 ∥	ND	580	12.5	UD	1,108.1	UD	10.2	UD	UD	40.9	0.96	1.00
		7.0	ND ¶	590.0	19.4	UD	993.0	UD	45.3	5.7	UD	84.2	0.84	0.96

All fermentations were in LB medium with glucose and the reported values were after 72 h, unless indicated otherwise. Cell yield is expressed in OD420 nm.

^*Qs, rate of glucose consumption—mmoles glucose consumed L^-1 h^-1

^†Product yield is presented as a fraction of theoretical yield from glucose (for lactate, the theoretical yield is two per glucose).

^‡Strain QZ4 also produced acetoin and 2,3-butanediol; pH 5.0 culture, 44.5 mM 2,3-butanediol; pH 7.0 culture, 31.6 mM acetoin, and 93.1 mM 2,3-butanediol. These two products were not detected in the broths from other cultures.

^§Evolved, various stages in evolution (Fig. S2).

^¶Due to the presence of CaCO₃ in the medium, the cell density of these cultures was not determined.

^∥Fermentation pH was maintained by addition of Ca(OH)₂ and cell density was not determined due to the presence of Ca-salts. UD—undetectable, less than 0.5 mM; Succ, succinate.