Table 1: Independent variables chosen for the CCD.

Factor Codes	Independent Variables	Unit	Coded Factor Levels
			-α	-1	0	+1	+α
X1	pH of media	-	3.9324	6	7.5	9	11.0676
X2	Inoculum age	hours	5.1885	30	48	66	90.8115
X3	Inoculum size	% (v/v)	2.3309	7.5	11.25	15	20.1691
X4	Fermentation period	hours	-13.623	36	72	108	157.623
X5	Incubation Temperature	°C	6.2159	20	30	40	53.7841
X6	Shaking speed	rev/min (rpm)	-3.381	100	175	250	353.381