Table 3.

Selected variables and their assigned levels by Box-Behnken Design (BBD).

Variables	Component	Range	Levels of Variables Studied
			−1	0	+1
A	Sucrose	100–400	10	200	400
B	Yeast extract	1.0–2.5	1.0	2.5	5.0
C	NH4Cl	0.10–10	1.0	5.0	10.0