Table 2: Twenty trials Plackett-Burman experimental design with the response.

TrialsPhysical variablesCarbon sourcesNitrogen sourcesEnergy sourceMetal ions Response enzyme activity
  (U/mL)
Moisture contentWeight of waste Initial pHGlucoseGrape fruitSucroseStarchMolassesPeptoneTryptoneYeast extractSoya beanNaNO3(NH4)2PO4KH2PO4MgSO4MnSO4CuSO4FeSO4Experimental Predicted

1+1−1−1−1−1+1+1−1+1+1−1−1+1+1+1+1−1+1−10.040.02
2+1−1+1+1−1−1+1+1+1+1−1+1−1+1−1−1−1−1+11.431.40
3+1+1−1+1+1−1−1+1+1+1+1−1+1−1+1−1−1−1−14.164.19
4−1−1+1+1+1+1−1+1−1+1−1−1−1−1+1+1−1+1+13.123.15
5−1+1−1+1−1−1−1−1+1+1−1+1+1−1−1+1+1+1+11.561.58
6−1−1−1−1+1+1−1+1+1−1−1+1+1+1+1−1+1−1+10.080.09
7−1+1+1−1+1+1−1−1+1+1+1+1−1+1−1+1−1−1−11.951.97
8−1−1+1+1−1+1+1−1−1+1+1+1+1−1+1−1+1−1−13.253.22
9−1+1−1−1−1−1+1+1−1+1+1−1−1+1+1+1+1−1+10.650.63
10+1−1−1+1+1+1+1−1+1−1+1−1−1−1−1+1+1−1+13.383.36
11+1+1−1−1+1+1+1+1−1+1−1+1−1−1−1−1+1+1−12.342.31
12−1+1+1−1−1+1+1+1+1−1+1−1+1−1−1−1−1+1+12.082.06
13−1−1−1−1−1−1−1−1−1−1−1−1−1−1−1−1−1−1−10.260.29
14−1−1−1+1+1−1+1+1−1−1+1+1+1+1−1+1−1+1−11.691.66
15+1−1+1−1+1−1−1−1−1+1+1−1+1+1−1−1+1+1+19.109.13
16−1+1+1+1+1−1+1−1+1−1−1−1−1+1+1−1+1+1−15.725.70
17+1+1−1+1−1+1−1−1−1−1+1+1−1+1+1−1−1+1+11.631.64
18+1+1+1+1−1+1−1+1−1−1−1−1+1+1−1+1+1−1−13.513.54
19+1+1+1−1+1−1+1−1−1−1−1+1+1−1+1+1−1−1+111.7011.67
20+1−1+1−1−1−1−1+1+1−1+1+1−1−1+1+1+1+1−16.506.52