Table 2 Statistical analysis of PBD showing coefficient, t-test values and p-values of variables influencing MB degradation

Constant

9.5833

0.1667

57.5

0.011

NaCL

 − 1.55

0.1667

 − 9.3

0.068

MgSO₄

 − 2.0667

0.1667

 − 12.4

0.051

KH₂PO₄

 − 1.8333

0.1667

 − 11

0.058

K₂HPO₄

0.6333

0.1667

3.8

0.164

NaNO₃

2.9

0.1667

17.4

0.037

Molasses

3.9333

0.1667

23.6

0.027

MB conc

 − 6.1

0.1667

 − 36.6

0.017

Inoculum size (%)

3.2667

0.1667

19.6

0.032

Incubation time (days)

1.0833

0.1667

6.5

0.097

pH

 − 4.9167

0.1667

 − 29.5

0.022

R² = 99.9

R² (adj) = 99.72