2.6. Screening of the supplemental nutrients using a PlackettBurman design.
PlackettBurman design, an efficient technique for medium component optimization , was employed for screening fermentation parameters that significantly influenced inulinase production. Each independent variable was tested at two levels, high and low, which were denoted by(+) and (−), respectively. In the present study, the supplemental nutrients were screened by a Plackett–Burman design for eleven variables at two levels (Table 1). The eleven assigned variables were screened in twelve experimental designs. All experiments were carried out in duplicate and the averages of inulinase activity were taken as response (Table 2).