Table 1 Variables in real values, for screening by Plackett–Burman design
Variables | Levels | Units | |
|---|---|---|---|
+1 | −1 | ||
A : pH | 5 | 9 | |
B : Colloidal chitin | 1 | 3 | % |
C : Date syrup | 0 | 2 | % |
D : Dummy | – | – | – |
E : Lactoserum | 0 | 2 | % |
F : Peptone | 10 | 15 | g/l |
G : Casein | 0.1 | 0.4 | g/l |
H : Dummy | – | – | – |
I : Tryptone | 10 | 15 | g/l |
J : Yeast extract | 0.1 | 0.4 | g/l |
K : Ammonium sulfate | 0.1 | 0.4 | g/l |
L : Dummy | – | – | – |
M : PO4 | 1 | 2 | g/l |
N : Trace elements | 0.5 | 1.5 | ml/l |
O : Crayfish shell | 0 | 20 | g/l |
P : Dummy | – | – | – |
Q : Mushroom | 0 | 20 | g/l |
R : Shrimp shell | 0 | 20 | g/l |
S : NaCl | 5 | 10 | g/l |