Table 5. Summarized data of analysis of variance (ANOVA) for enhancing biomass production according to response surface methodology (RSM)

Sources Coefficient estimate Sum of squares Degree of freedom Mean square Standard error F-value p-value, Prob>F
Model 12.27 401.42 9 44.60 0.86 26.50 0.0004****4)
X11) 3.95 249.88 1 249.88 0.32 148.44 <0.0001****
X2 2) 1.72 47.14 1 47.14 0.32 28.00 0.0018***
X3 3) 0.95 14.56 1 14.56 0.32 8.65 0.0259**
X1X2 1.59 20.30 1 20.30 0.46 12.06 0.0133**
X1X3 -1.01 8.10 1 8.10 0.46 4.81 0.0707*
X2X3 -0.66 3.51 1 3.51 0.46 2.08 0.1990
X1 2 1.61 41.41 1 41.41 0.32 24.60 0.0026***
X2 2 0.14 0.30 1 0.30 0.32 0.18 0.6873
X3 2 0.041 0.027 1 0.027 0.32 0.016 0.9039
Residual 10.10 6 1.68
Lack of fit 10.08 5 2.02
Pure error 0.016 1 0.016
Cor Total 411.52 15
Standard deviation 1.30 Press 84.70
Mean 14.05 R-squared 0.9755
Coefficient of variation (%) 9.23 Adjusted R-squared 0.9386
1) X1, molasses.
2) X2, sucrose.
3) X3, peptone.
4)*, **, ***, **** indicate significance at p<0.1, 0.05, 0.01, 0.001 respectively.