Table 1: Range of experiment and the variables level.

Factor Coding - α -1 0 +1
A (Temperature, oC) 33.18 40 50 60 66.82
B (Total solid content, %) 2.64 4 6 8 9.36
C (Feed/inoculums ratio) 1:1.66 1:2 1:2.5 1:3 1:3.34