Figure 5. Effect of agitation intensity on the production of citric acid by Aspergillus niger GCMC-7 in stirred fermentor.

Sugar added: 150 g/l.
Air supply: 1.0 l/l/min.
Initial pH: 6.0.
Fermentation period: 144 h.
Incubation temperature: 30ºC.
The error bars indicate the standard deviation among the three parallel replicates.