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Table 4 ANOVA and regression coefficients of the second-order polynomial model for the response variables

From: Application of response surface methodology to improve the production of antimicrobial biosurfactants by Lactobacillus paracasei subsp. tolerans N2 using sugar cane molasses as substrate

Factors Yield Surface tension Inhibition diameter
DF Coefficients Sum of squares F-value p-value DF Coefficients Sum of squares F-value p-value DF Coefficients Sum of squares F-value p-value
X0, constant   2.546      37.402      60.776    
Linear
X1: Peptone 1 0.246 0.771 29.63 0.0028** 1 − 3.023 115.658 85.14 0.0003*** 1 5.979 437.292 16.78 0.0094**
X2: Temperature 1 0.157 0.311 11.98 0.0180* 1 − 1.072 14.542 10.70 0.0222* 1 3.051 117.763 4.52 0.0868
X3: Molasses 1 0.218 0.603 23.21 0.0048** 1 − 2.843 101.647 74.82 0.0003*** 1 3.778 180.6 6.93 0.0464*
Quadratic
X 21 1 − 0.458 2.267 87.14 0.0002*** 1 3.790 155.245 114.28 0.0001*** 1 − 7.283 573.377 22.01 0.0054**
X 22 1 − 0.864 8.079 310.44 0.0000*** 1 7.287 573.95 422.49 0.0000*** 1 − 21.376 4938.56 189.55 0.000***
X 23 1 − 0.322 1.124 43.21 0.0012** 1 3.194 110.272 81.17 0.0003*** 1 − 10.777 1255.19 48.18 0.0010**
Interaction
X 1 X 2 1 0.094 0.072 2.77 0.1571 1 − 0.735 4.321 3.18 0.1346 1 − 0.161 0.208012 0.01 0.9323
X 1 X 3 1 − 0.395 1.248 47.99 0.0010** 1 5.192 215.696 158.78 0.0001*** 1 − 9.368 702.188 26.95 0.0035**
X 2 X 3 1 − 0.070 0.039 1.51 0.2736 1 0.367 1.080 0.80 0.4133 1 − 0.243 0.475313 0.02 0.8978
Lack of fit 5   0.401 3.08 0.1209 5   27.329 4.02 0.0764 5   109.353 0.84 0.5738
Pure error 5   0.130    5   6.792    5   130.269   
Total (corr.) 19   15.050    19   1326.53    19   8445.28   
R2 (%)   96.46      97.15      97.42    
Adjusted R2 (%)   93.29      94.59      95.11    
AAD   0.012      0.03      0.026    
A f   1.11      1.08      1.08    
B f   1.04      0.99      0.99    
  1. DF: degrees of freedom; *significant at p < 0.05, **significant at p < 0.01, ***significant at p < 0.001