Optimization of Hydrothermal and Diluted Acid Pretreatments of Tunisian Luffa cylindrica (L.) Fibers for 2G Bioethanol Production through the Cubic Central Composite Experimental Design CCD: Response Surface Methodology

Table 2

Theoretical matrix of cubic central composite experimental design CCD for optimization of diluted acid pretreatment of Luffa cylindrica fibers.

	Experiments	Temperature (°C)	Reaction time (min)	Acid concentration (%)
A	1	−1	−1	−1
	2	−1	−1	−1
	3	−1	−1	−1
B	4	+1	−1	−1
	5	+1	−1	−1
	6	+1	−1	−1
C	7	−1	+1	−1
	8	−1	+1	−1
	9	−1	+1	−1
D	10	+1	+1	−1
	11	+1	+1	−1
	12	+1	+1	−1
E	13	−1	−1	+1
	14	−1	−1	+1
	15	−1	−1	+1
F	16	+1	−1	+1
	17	+1	−1	+1
	18	+1	−1	+1
G	19	−1	+1	+1
	20	−1	+1	+1
	21	−1	+1	+1
H	22	+1	+1	+1
	23	+1	+1	+1
	24	+1	+1	+1
I	25	−1	0	0
	26	−1	0	0
	27	−1	0	0
J	28	+1	0	0
	29	+1	0	0
	30	+1	0	0
K	31	0	−1	0
	32	0	−1	0
	33	0	−1	0
L	34	0	+1	0
	35	0	+1	0
	36	0	+1	0
M	37	0	0	−1
	38	0	0	−1
	39	0	0	−1
N	40	0	0	+1
	41	0	0	+1
	42	0	0	+1
O	43	0	0	0
	44	0	0	0
	45	0	0	0