This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5-dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine-acetic anhydride methods. The studies revealed that production parameters pH, inoculum size, substrate concentration, incubation temperature, and fermentation period had profound effect on the amount of citric acid produced.
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.
Citric acid is a tricarboxylic acid Figure 1 with a molecular weight of It is a primary metabolic product formed in the tricarboxylic acid or Krebs cycle and is found in small quantities in virtually all plants and animals, being isolated from lemon juice in Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries.
It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp.
from different sources of carbohydrates, such as molasses and starch based media. Aspergillus niger is cultured for the industrial production of many substances. Various strains of A. niger are used in the industrial preparation of citric acid (E) and gluconic acid (E) and have been assessed as acceptable for daily intake by the World Health Organisation.
A. niger. spores/L may be introduced to the fermentor. - Aeration is provided to the fermenter by air sparging ( vvm) Industrial Production of Citric Acid.
Separation: The biomass is separated by filtration - The liquid is transferred to recovery process.
biochemical factors that contribute to citric acid accumu-lation in A. niger fermentations. 2. Fermentation conditions The biochemical mechanism by which A.
niger accumulates citric acid has attracted much interest. Fermentation conditions were established during the s and s when the effects of various medium components were evaluated. Advances in citric acid fermentation by Aspergillus niger: Biochemical aspects, membrane transport and modeling.
Author The level of glucose had a marked effect on citric acid production rate.
The specific rate of citric acid production increased with increasing initial glucose concentration (batch culture) or increasing constant glucose. The efficiency of current methods for industrial production of citric acid is limited. To achieve continuous citric acid production with enhanced yield and reduced cost, immobilized fermentation was employed in an Aspergillus niger repeated fed-batch fermentation system.
We developed a new type of material (PAF), which was used as a carrier for the novel adsorption immobilization system.