Table 3. Results of fermentation carried out using strain DA-3 with different concentrations of metal ions and vitamins.

Metal ions/vitamins levels	Controla	A	B	C
Consumed glucose (g L−1)	96.9±1.9	96.4±2.5	96.8±3.6	97.3±2.7
Specific growth rate (1 h−1)	0.12±0.01	0.12±0.02	0.19±0.03	0.13±0.01
Biomass (g L−1)	9.3±0.05	9.3±0.4	15.3±0.7	11.2±0.4
Diacetyl (g L−1)	0.95±0.07	2.1±0.2	3.5±0.2	4.7±0.4
α-Acetolactate (g L−1)	0.86±0.05	0.18±0.02	0.25±0.01	0.24±0.03
Acetoin (g L−1)	0.11±0.00	0.18±0.01	0.51±0.03	0.32±0.02
Butanediol (g L−1)	0.08±0.00	0.15±0.02	0.36±0.02	0.61±0.05
Yield (g (g glucose)−1)b
Diacetyl	0.01	0.02	0.04	0.05
Ethanol	0.02	0.02	0.12	0.13
Biomass	0.10	0.10	0.16	0.12
Pyruvate	0.38	0.36	0.16	0.10

^aControl: 0 mM FeCl₃, 0.02 mg L⁻¹ VB₁, 8 mg L⁻¹ NA.

A: 20 mM FeCl₃, 0.02 mg L⁻¹ VB₁, 8 mg L⁻¹ NA.

B: 20 mM FeCl₃, 0.08 mg L⁻¹ VB₁, 8 mg L⁻¹ NA.

C: 20 mM FeCl₃, 0.08 mg L⁻¹ VB₁, 2 mg L⁻¹ NA.

VB₁ and NA represent thiamine and nicotinic acid, respectively.

^bThe standard deviation for each yield was below 10%.