Table 1.

Experimental range of factors studied using CCD in terms of coded and actual factors

Factors	Symbols	Actual levels of coded factors
		−1 (low)	0 (middle)	+1 (high)
Time of incubation (days)	A	10	11	12
pH	B	7	8	9
Temperature (°C)	C	25	30	35
Sucrose concentration (%w/v)	D	1	2	3
Soya peptone concentration (%w/v)	E	0.5	1.0	1.5