Citric acid production by pellet growth ofAspergillus niger

A. niger (5) ( ) . (0.5-2.5%) (1000) (0.7-1.3) / (25-40) (24-188) (1%) 400 1000 (0.7) / (30) (144) (53) / .Citric acid production by submerged fermentation with pellet growth of Aspergillus niger in stirred fermentor with five liter capacity and (2.5) liter working volume .Different cultural conditions such as inoculum volume with range (0.5-2.5%), air supply with range (0.7-1.3) v/v, agitation in one stage 1000 rpm and two stages (400) and (1000) rpm, incubation temperature with range (25-40 C0) , and time profile after inculcation with range of (24-188 hours) , and we found that inoculum volume (1%), air supply 0.7 v/v agitation with two satge 400 and 1000 rpm, incubation temperature,30C0, were optimized for enhance citric acid production. Maximum amount of citric acid obtained during this study was (53.0 g/l).