Citric Acid Production by Immobilized Aspergillus Niger on Starch Hydrolysate Medium

Abstract

Citric acid is the most produced and widely used organic acid — its current market is upwards of 300 000 tones per annum. Two processes are used in citric acid production in which special strains of Aspergillus niger are employed: surface and submerged fermentations. Although the basic “know-how” is well known yields are usually low. Considerable efforts have been focused in the last decade on the development of improved fermentation methods especially with immobilized cells. Despite the cultivation method the experimental protocols use either pure glucose or sucrose and industrial production is still based mainly on molasses.