Optimization to Hydrothermal Liquefaction of Low Lipid Content Microalgae Spirulina sp. Using Response Surface Methodology

Table 5

Test of significance of the quadratic equation coefficient and ANOVA for the response surface quadratic model.

Source	Sum of squares	df	Mean square	value	value prob. >
Model	120.41	9	13.38	23.02	<0.0001
	15.56	1	15.56	26.77	0.0004
	26.66	1	26.66	45.87	<0.0001
	3.66	1	3.66	6.3	0.0309
	2.64	1	2.64	4.55	0.0587
	0.045	1	0.045	0.077	0.7865
	0.6	1	0.6	1.04	0.3316
	16.45	1	16.45	28.3	0.0003
	27	1	27	46.46	<0.0001
	41.01	1	41.01	70.57	<0.0001
Residual	5.81	10	0.58	—	—
Lack of fit	4.24	5	0.85	2.70	0.1502
Pure error	1.57	5	0.31	—	—
Cor. total	126.22	19	—	—	—

, concentration; , temperature; , holding time. The determination coefficient (R²) of the regression model is 0.9540.