Table 1: Media components and test levels for Plackett–Burman experiment.

VariableVariable codeLow level (−1)High level (+1)

Moisture content (mL)A 1050
Weight of waste (g)B 520
Initial pHC 4.57.5
Glucose (%)D 13
Grape fruit (%)E 13
Sucrose (%)F 13
Starch (%)G 13
Molasses (%)H 13
Peptone (%)J 00.5
Tryptone (%)K 00.5
Yeast extract (%)L 00.5
Soya bean (%)M 00.5
NaNO3 (%)N 00.5
(NH4)2PO4 (%)O 00.5
KH2PO4 (%)P 0.10.5
MgSO4 (mM)Q 05
MnSO4 (mM)R 05
CuSO4 (mM)S 05
FeSO4 (mM)T 05

Weight of waste (g): orange rind (substrate).