Table 2 Factors and responses information of Plackett–Burman design (*monosaccharide carbohydrate).

Variables

A

Agitation speed

rpm

80

160

B

Fermentation time

h

24

48

C

Seed liquid volume

% v/v

3

10

D

Carbone* source

–

Fructose

Glucose

E

Carbone concentration

g/l

5

20

F

Tween 80

% w/v

0

0.2

G

FeSO₄

mg/ml

0.3

8

H

NH₄Cl

g/l

2

4

J

KH₂PO₄

g/l

1

3

K

ZnSO₄

ug/ml

100

1000

L

Siderophore

ug/ml

0

16

Fixed factors

MgCl₂.6H2O

g/l

0.1

Peptone

g/l

23

Fermentation volume

ml

100

Iron adding time

h

Log phase

Siderophore adding time

h

Log phase

Temperature

°C

37

pH

–

5.5

Type of yeast

–

S. boulardii

Response

R₁

Biomass Weight

g/l

–

R₂

Organic Iron content

–

–