SUITABILITY OF STRAINS AND MUTANTS OF ASPERGILLUS-NIGER FOR THE PRODUCTION OF CITRIC-ACID FROM CHEESE WHEY

Three strains of Aspergillus niger CAIM 111, CAIM 132 and CAIM 167, we re used to produce citric acid from whey using the shaking fermentatio n technique. The fermentation process was monitored using lactose conc entration, utilized lactose, citric acid concentration, conversion coe fficient of lactose to citric acid, and mycelial dry weight. A. niger CAIM 111 and A. niger CAIM 167 exhibited a high ability to convert lac tose in whey to citric acid, i.e. 1.06 g/l and 0.82 g/l, respectively, while A. niger CAIM 132 produced only 0.05 g/l citric acid. Three mut ants from each parent strain A.niger CAIM 111 and A. niger CAIM 167 sh ared a lower ability to produce citric acid from whey than their paren ts. The two parent strains were selected to maximize the utilization o f cheese whey for the production of citric acid.