ABSTRACT
This work provides a review about the biotechnological production of citric acid starting from the
physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors.
Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and
phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus.
Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies
employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger,
and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are
also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks
for the bioproduction of citric acid.