Abstract            Volume:8  Issue-8  Year-2020         Original Research Articles

Online ISSN : 2347 - 3215 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcret@gmail.com

The first individual process for citric acid production was the liquid surface culture which was introduced in 1919 in Belgium, and in 1923 in US. After that, other methods of fermentation, such as submerged fermentation were developed. Although this technique is more sophisticated, surface method required less effort in operation and installation and energy cost. The main aim of this review is to detail the microbial community during this fermentation, raw materials, recovery methods and type of reactor they use. Organic acids such as citric, malic and pyruvic are used extensively as acidulants in the food industry. Inulin, a fructose polymer found as a carbohydrate reserve in plants, was investigated as a possible substrate for organic acid production. Aeration was found to have a significant effect on acid production. Submerged fermentation of inulin produced a higher yield of citric acid than surface fermentation with optimum acid production occurring at a concentration of 14%. An investigation into the enzymes produced during citric acid fermentation by Aspergillus niger revealed that both extracellular and cell lysate invertase and inulinase were produced during fermentation. Citric acid cannot be recovered directly from the fermented liquor by crystallization because of excess of impurities. It has got several other applications in various other fields. Currently, the global production of citric acid is estimated to be around 736000 tones/year, and the entire production is carried out by fermentation.

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