Statistical optimization of chitinase production by Streptomyces rubiginosus SP24 and efficacy of purified chitinase to control root-knot nematode infection in Vigna radiata under controlled conditions

Chemical and Biological Technologies in Agriculture

Table 2 Optimization of variables using Plakett–Burman design for production of chitinase showing the actual and predicted values in terms of U/ml

Run	Colloidal chitin	Peptone	Beef extract	Xylose	Sucrose	Magnesium sulfate	Dihydrogen potassium phosphate	Calcium carbonate	Actual chitinase activity	Predicted chitinase activity
1	1	− 1	1	− 1	1	1	− 1	− 1	1.78	1.57
2	1	− 1	− 1	1	− 1	1	− 1	1	2.02	2.06
3	− 1	1	1	− 1	− 1	1	− 1	1	1.28	1.38
4	1	1	− 1	1	1	− 1	− 1	− 1	2.36	2.29
5	− 1	1	− 1	1	− 1	1	1	− 1	1.36	1.38
6	− 1	1	1	1	1	− 1	− 1	1	1.96	1.88
7	1	− 1	1	1	− 1	− 1	1	1	1.36	1.56
8	− 1	− 1	− 1	− 1	− 1	− 1	− 1	− 1	0.96	1.16
9	− 1	− 1	− 1	− 1	1	− 1	1	1	0.78	0.66
10	1	1	1	− 1	− 1	− 1	1	− 1	1.42	1.3
11	− 1	− 1	1	1	1	1	1	− 1	1.28	1.15
12	1	1	− 1	− 1	1	1	1	1	1.16	1.3

Level (− 1 and 1) defines low and high coded values corresponding to the variable (colloidal chitin—0.1 and 1 gm, peptone—0.1 and 2, beef extract—0.1 and 2.0, xylose—0.2 and 2, sucrose—0.2 and 2, magnesium sulfate—0.1 and 0.5, dihydrogen potassium phosphate—0.1 and 0.4, calcium carbonate—0.1 and 0.5)