| Independent variable |
Coefficient Symbol |
Soluble proteins(1) (Y1) |
NH2 –free amino groups (2) (Y2) |
| Estimate |
t-value |
P-value |
% confidence |
Estimate |
t-value |
P-value |
% confidence |
| B0 |
0.1095 |
24.1899 |
6.99E-05* |
99.99 |
45.7075 |
19.1920 |
0.000327* |
99.97 |
| X1: Feather % (W/V) |
B1 |
0.0265 |
5.85419 |
0.00274* |
99.726 |
12.1592 |
5.10548 |
0.015578* |
98.44 |
| X2:Peptone % (W/V) |
B2 |
0.0005 |
0.11045 |
0.118777 |
|
-0.9925 |
-0.416 |
0.807205 |
|
| X3:Yeast extract % (W/V) |
B3 |
0.0190 |
4.19734 |
0.006028* |
99.3972 |
5.61083 |
2.35592 |
0.106506 |
|
| X4:NH4Cl % (W/V) |
B4 |
-0.02267 |
-5.0073 |
0.002601* |
98.9103 |
9.33083 |
3.917901 |
0.030684 |
|
| X5:Time (hrs) |
B5 |
0.007333 |
1.62002 |
0.010897 |
98.9103 |
4.83417 |
2.02981 |
0.137648 |
|
| X6:Inoculum size % (V/V) |
B6 |
0.052333 |
11.5611 |
0.001033* |
99.8967 |
1.4641 |
0.61479 |
0.575616 |
|
| X8:Casamino acids % (W/V) |
B7 |
0.0060 |
1.32547 |
0.978258 |
|
-6.00083 |
-2.51968 |
0.088292 |
|
| X8:K2HPO4 % (W/V) |
B8 |
-0.01067 |
-2.356 |
0.898196 |
|
-1.40583 |
-0.59029 |
0.617889 |
|
|
| • Highlighted significant model terms are taken at P ≤ 0.006 for the soluble protein model.
• Highlighted significant model terms are taken at P ≤ 0.02 for the NH2-free amino groups model.
(1): R2=0.99 and adjusted R2=0.97
(2): R2=0.95 and adjusted R2=0.85 |
| Table 4: Regression summary for full polynomial equation for end products of feather biodegradation upon using PBD. |
