Optimization of Citric Acid Production through Manipulation of Cultural Conditions of Aspergillus Niger

An Aspergillus niger isolate was screened for citric acid production from glucose and the cultural conditions were manipulated for optimum citric acid production. Optimization studies improved citric acid yield by 13.34% from 12.81 g/l obtained during the screening test to 14.52 g/l obtained at the end of the optimization studies. Glucose concentration of 15%, pH of 5.5, methanol at 3% concentration (v/v) and agitation rate of 450 rpm were found to be more suitable for citric acid production by the Aspergillus niger isolate used in this studies. Keywords : Citric acid, Aspergillus niger , Submerged fermentation, cultural conditions