Table 4.

ANN analysis and modeling comparison of predictive capability between CCD and ANN for AuNPs biosynthesis using Streptomyces flavolimosus cell-free supernatant as affected by temperature (°C), incubation period (days), HAuCl₄ concentration (µg/mL) and initial pH level.

Measure	ANN		Overall model performance
	Training	Validation	Statistics	Measures of fit for CCD	Measures of fit for ANN
R2	0.9989	0.9967	R2	0.9885	0.9981
RASE	5.54	10.67	RASE	18.72	7.64
MAD	2.93	7.95	AAE	15.89	4.60
SSE	612.82	1138.01	Freq	30	30
Sum freq	20	10

MAD mean absolute deviation, SSE the sum of squares error, RASE root average squared error, AAE average absolute error for each model.