ABSTRACT
Microbial citric acid (CA) is a widely utilized organic acid in a variety of industries, including food, pharmaceuticals, detergents, beverages, and cosmetics. CA is in high demand around the world due to its numerous industrial applications. Current developments in microbial fermentation techniques for CA synthesis are reviewed in this chapter. Several biodegradable organic waste products are generated in substantial quantities in the food, beverage, milk, and sugar manufacturing industries. Sugarcane bagasse, grape pomace, apple pomace, pineapple pomace, vegetables, tapioca, coconut husk, banana peels, citrus peels, whey, and decaying fruits have all been discovered to be possible CA substrates. For further development in the fermentation process, a considerable effect of substrate concentration, inorganic salts, starting sugar concentration, moisture, and additions has been highlighted. Recent improvements in CA production’s upstream and downstream processes are also extensively explored. This review sheds light on the future prospects of a cost-effective fermentation process for the manufacture of CA from a variety of low-cost source materials. The production of CA as an industrial by-product will aid in waste disposal and minimize industry’s reliance on other CA manufacturers. As a result, the sector would benefit both environmentally and commercially.
