Heterologous expression and optimization using experimental designs allowed highly efficient production of the PHY US417 phytase in Bacillus subtilis 168

AMB Express

Table 3 Box Behnken factorial experimental design representing response of phytase activity (U ml^-1) as influenced by shaking speed and concentration of yeast extract and ammonium sulphate

Exp	X1	X2	X3	Phytase activity (U ml^-1)	Phytase activity predicted (U ml^-1)
1	300	5	10	35.73 ± 0.17	35.18
2	300	15	10	42.92 ± 0.21	43.36
3	250	5	5	30.15 ± 0.15	29.86
4	250	5	15	33.10 ± 0.13	34.43
5	250	15	5	34.51 ± 0.2	32.79
6	250	15	15	35.79 ± 0.17	37.37
7	200	10	5	17.51 ± 0.08	18.75
8	300	10	5	38.62 ± 0.19	39.89
9	200	10	15	24.57 ± 0.12	23.33
10	300	10	15	45.63 ± 0.36	44.47
11	250	10	10	34.36 ± 0.17	36.52
12	250	10	10	34.93 ± 0.10	36.52
13	250	10	10	41.17 ± 0.23	36.52