Table 4.

Effect of the combination of multiple nutrient sources and incubation conditions on avicin A production.

Run No	Nutrient sources		Incubation conditions			Bacteriocin activity (BU/ml)
	Carbon source	Nitrogen source	pH	Time (hours)	Temperature (°C)
1	Lactose	Protease peptone	7	18	30	320
2	Lactose	Protease peptone	7	30	20	10
3	Lactose	Protease peptone	8	18	20	640
4	Lactose	Protease peptone	8	30	30	80
5	Lactose	Peptone	7	18	20	160
6	Lactose	Peptone	7	30	30	20
7	Lactose	Peptone	8	18	30	640
8	Lactose	Peptone	8	30	20	10
9	Mannitol	Protease peptone	7	18	20	320
10	Mannitol	Protease peptone	7	30	30	40
11	Mannitol	Protease peptone	8	18	30	320
12	Mannitol	Protease peptone	8	30	20	10
13	Mannitol	Peptone	7	18	30	80
14	Mannitol	Peptone	7	30	20	40
15	Mannitol	Peptone	8	18	20	80
16	Mannitol	Peptone	8	30	30	20

Five variables (i.e., mannitol and lactose as carbon sources; peptone and protease peptone as nitrogen sources; pH; incubation time; and incubation temperature) having the highest influence on avicin A production were selected based on preliminary experiments. According to the 2-level 5 variables concept, a 2^5-1 fractional design was considered, which lead to the 16 runs listed.