Table 1.

Comparisons of acetoin production from glucose

Strain	IPE5-4	IPE5-4-UD-4
Fermentation process	Shake flask	Shake flask	Fermenter
Substrate consumption
Substrate concentration (g L−1)	99.92 ± 0.91	101.83 ± 3.81	120.94 ± 4.02
Substrate consumption time (h)	72	72	48
Concentration of residual substrate (g L−1)	52.98 ± 1.93	52.28 ± 2.19	35.38 ± 2.34
Consumption rate of substrate (g L−1 h−1)a	0.65	0.69	1.78
Acetoin production
Maximum concentration (g L−1)	11.45 ± 0.11	17.20 ± 0.19	28.83 ± 0.65
Acetoin yield (g g−1)b	0.24	0.35	0.34
Acetoin productivity (g L−1 h−1)c	0.16	0.24	0.60
CAcetoin/CdGlucose	0.33 ± 0.01	0.47 ± 0.03	0.46 ± 0.02

^aConsumption rate of substrate was calculated by [initial concentration of specific substrate (g L⁻¹) − residual concentration of specific substrate (g L⁻¹)]/substrate consumption time (h)

^bAcetoin yield was calculated by g acetoin/g consumed substrate

^cAcetoin productivity was calculated by maximum concentration of acetoin (g L⁻¹)/substrate consumption time (h)

^d C _Acetoin meant the molar concentration of carbon in acetoin, and C _Glucose meant the molar concentration of carbon in glucose