Table 1 Gradient setting of each factor in the single-factor optimization experiment.
Concentration gradient setting | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Orange peel (g/L) | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | ||
Single-factor optimization for media | Type of nitrogen source (g/L) | NH4Cl | 1.5 | – | – | – | – | – | – | – | – | – |
(NH4)2SO4 | 1.5 | – | – | – | – | – | – | – | – | – | ||
(NH4)2HPO4 | 1.5 | – | – | – | – | – | – | – | – | – | ||
NaNO3 | 1.5 | – | – | – | – | – | – | – | – | – | ||
Casein | 1.5 | – | – | – | – | – | – | – | – | – | ||
Peptone | 1.5 | – | – | – | – | – | – | – | – | – | ||
Yeast extract | 1.5 | – | – | – | – | – | – | – | – | – | ||
Peptone & yeastextract (2:1 ratio respectively ( | 1.5 | – | – | – | – | – | – | – | – | – | ||
Fermentation condition single-factor optimization | Peptone &yeast extract (g/L) (2:1 ratio respectively ( | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 4 | – | – | – | |
Incubation time (h) | 12 | 24 | 36 | 48 | 60 | 72 | 84 | 96 | – | – | ||
Inoculation size (%) (v/v) | 1 | 2 | 4 | 6 | 8 | 10 | 12 | - | – | – | ||
Initial pH | 5 | 6 | 6.5 | 7 | 7.5 | 8 | 9 | 10 | – | – | ||
Salinity (%) | 0 | 2 | 5 | 7.5 | 12.5 | 15 | 17.5 | 20 | – | – | ||
Temperature (oC) | 25 | 30 | 35 | 37 | 40 | 45 | 50 | – | – | – | ||
Agitation rate (rpm) | 0 | 50 | 150 | 200 | 250 | – | – | – | – | – | ||
