Effects of Fermentation Conditions on Citric Acid Production from Beet Molasses by Aspergillus niger

Abstract

The effects of initial sugar concentration, pH and temperature on citric acid production from beet molasses by Aspergillus niger were investigated in shake cultures. The maximum citric acid production (52.3 g L^-1) was achieved at the condition where the initial sugar concentration was 140 g L^-1 at pH 5.0, 30 ºC. When the fermentation was performed in the treated medium the citric acid concentration increased from 14.3 to 33.2 g L^-1. Beet molasses is a suitable substrate for citric acid production by A. niger and this organism is sensitive to pH, temperature and sugar concentration in the medium.