Figure 2. Time profile of citric acid fermentation by Aspergillus niger GCMC-7 in stirred fermentor.

Sugar added: 150 g/l.
Agitation intensity: 200 rpm.
Air supply: 1.0 l/l/min.
Initial pH: 6.0.
Incubation temperature: 30ºC.
The error bars indicate the standard deviation among the three parallel replicates.