Optimization of chromium and tannic acid bioremediation by Aspergillus niveus using Plackett–Burman design and response surface methodology

AMB Express

Table 3 Box–Behnken experimental design of A. niveus

Run	A: glucose g/L	B: tannic acid %	C: metal dose ppm	D: NH₄Cl g/L	Cr removal %		Residual TA %
Run	A: glucose g/L	B: tannic acid %	C: metal dose ppm	D: NH₄Cl g/L	A* value	P* value	A* value	P* value
1	0	+ 1	− 1	0	80.97	82.39	49.03	49.10
2	0	+ 1	0	+ 1	86.11	85.54	49	48.94
3	− 1	− 1	0	0	89.42	90.50	4.38	4.38
4	0	0	+1	− 1	89.98	90.13	26.32	26.37
5	+1	0	0	+ 1	84.21	84.50	26.29	26.28
6	0	0	0	0	89.84	88.66	26.3	26.26
7	+ 1	0	− 1	0	83.66	83.55	26.33	26.31
8	− 1	0	− 1	0	83.81	82.91	26.59	26.55
9	0	0	− 1	+ 1	83.26	83.21	26.47	26.45
10	+ 1	0	0	− 1	–		–
11	+ 1	+ 1	0	0	89.54	88.57	48.84	48.88
12	0	0	0	0	90.61	88.66	26.26	26.26
13	0	0–1	0	+ 1	88.85	89.25	4.47	4.39
14	0	0	+ 1	+ 1	85.67	85.06	26.27	26.37
15	0	0	0	0	85.76	88.66	26.3	26.26
16	0	0	− 1	− 1	78.12	78.82	26.54	26.48
17	0	0	0	0	89.14	88.66	26.28	26.26
18	+ 1	− 1	0	0	90.62	91.16	4.29	4.34
19	+ 1	0	+ 1	0	89.40	89.67	26.45	26.39
20	− 1	0	0	+ 1	88.13	88.69	26.4	26.47
21	0	+ 1	0	− 1	88.51	87.48	48.98	48.96
22	0	− 1	− 1	0	86.73	85.68	4.26	4.34
23	0	− 1	+1	0	91.94	91.08	4.45	4.45
24	− 1	0	+1	0	90.48	89.95	26.34	26.26
25	− 1	+1	0	0	89.31	88.88	48.97	48.95
26	0	0	0	0	87.91	88.66	26.17	26.26
27	− 1	0	0	− 1	84.38	84.66	26.28	26.35
28	00	− 1	0	− 1	88.06	87.99	4.45	4.41
29	00	+1	+1	0	88.54	90.15	48.81	48.80