Table 2.

Placket-Burman design table with organic selenium (selenium biotransformation) results. A-K are screening parameters and trails No. 13 to 17 are center points. The amount obtained for organic selenium is derived from experimental data.

Trial No.		Vaiables											Organic selenium
		A	B	C	D	E	F	G	H	I	J	K
	Unit	mg/L	Cº	h	g/L	pH	rpm	%	mL	H	h	g/L	(ppm)
1		25	31	24	25	7	250	1	50	0	72	7	1350
2		5	31	48	15	7	250	3	50	0	24	13	1580
3		25	25	48	25	4	250	3	100	0	24	7	2850
4		5	31	24	25	7	150	3	100	9	24	7	1425
5		5	25	48	15	7	250	1	100	9	72	7	1175
6		5	25	24	25	4	250	3	50	9	72	13	1419
7		25	25	24	15	7	150	3	100	0	72	13	1291
8		25	31	24	15	4	250	1	100	9	24	13	1021
9		25	31	48	15	4	150	3	50	9	72	7	1740
10		5	31	48	25	4	150	1	100	0	72	13	517
11		25	25	48	25	7	150	1	50	9	24	13	1363
12		5	25	24	15	4	150	1	50	9	24	7	658
13		15	28	36	20	5	200	2	75	4.5	48	10	1457
14		15	28	36	20	5	200	2	75	4.5	48	10	1504
15		15	28	36	20	5	200	2	75	4.5	48	10	1551
16		15	28	36	20	5	200	2	75	4.5	48	10	1598
17		15	28	36	20	5	200	2	75	4.5	48	10	1645