Table 5. Comparison of diacetyl production with the addition of different concentrations of Fe²⁺ or Mn²⁺ ions

Concentration (%, w/v)	Diacetyl from LRCC5306 (mg/L)
Concentration (%, w/v)	Iron	Manganese
0	42.28±1.58	43.66±2.09
0.0001	43.03±1.76	42.18±1.76
0.001	66.58±2.73^a	62.25±0.78^a
0.01	66.52±2.82^a	62.96±2.12^a
0.1	63.60±1.45^a	61.25±1.20^a
1.0	65.46±2.34^a	60.83±2.42^a

Results are expressed as mean±SE (n=3).
MRS broth was used as the basal medium, citrate was added before sterilization (autoclave, 121°C, 15 min). The initial concentration of diacetyl was 0.
Means in the same column with different lowercase superscript letters are significantly different at p<0.05.