Isolated Ctric Acid from Lemon Juice

Scheele (1784) isolated citric acid from lemon juice. Italy was the main was the main producer of citric acid from unripe lemon juice and some 90 percent of the world supply of calcium citrate came from the country. Citric acid from natural sources is now produced in a number of locations, especially, California, Hawaii and West Indies. The importance of natural citric acid has, however, greatly diminished since the development of fermentation process from sugar solution.

Wehmer (1893) described the production of citric acid by mould fermentation. He designated the mould as Citromyces and later reported that penicllium and Mucor could produce similar reaction.

Currie (1917) pointed out that strains of Aspergillus niger were infact best for the fermentative production of citric acid.

Porges (1932) reported the effect of different concentrations of sugar, inorganic nutrients, temperature and incubation periods on the production of citric acid from cane sugar. He found that the highest yield of citric acid was obtained with NaNO3, 4.0, K2HPO4 1.0, KCl 0.5 and MgSO4.7H2O gm when incubated for 7 days with 16 percent sugar concentration at 280C to 30oC.

 

Galbraith and Smith (1969) studied the filamentous growth of Aspergillus niger in submerged shake culture process for citric acid production and reported that Aspergillus niger grow in filamentous or pellet from depending on medium pH in submerged culture and concluded that pellet form is more suitable for citric acid production.

Khan et al. (1970) reported the effect of different concentrations of sugar, inorganic nutrients and different pH values of the fermentation medium on the citric acid production from cane molasses. The use of molasses in final sugar concentration of 12.5 to 15 percent was found to be best. The initial pH ranging from 3.5 to 6.0 in the molasses solution was found suitable for citric acid production. The concentration of added inorganic salts did not exceed, 4.0 g NaNO3 1.0 g KH2PO4, 7H2O 0.2 g, FeCl3 and 0.001 g MnCl2. H2O in the fermentation medium of local cane molasses. At higher concentration of salts fungal growth was increased and the citric acid production was decreased. As a source of nitrogen, peptone was inferior to sodium nitrate and potassium nitrate whose effect appeared to be the same in the citric acid production.

Banik (1975) during mutation studies on Aspergillus niger strains observed that Aspergillus niger AB 180 produced the high amount of citric acid (60.0 mg/ml) from sucrose at a level of 15 percent. The optimum concentration of NH4NO3 was 2.2 mg/ml. The optimal conditions were pH 3.5; temperature 27oC, incubation period 9 days. The yield was 80.2 mg/ml. Addition of sodium monofluoracetate (50 g/l) to the fermentation medium increased the citric acid production to 120.4 mg/ml.

Kubicek et al. (1977) studied the influence of manganese on enzyme synthesis and citric acid accumulation by Aspergillus niger and investigated that citric acid production is possible under excessive nitrogen condition provided that phosphate ions are limiting.

Jerzy et al. (1980) found that optimum temperature for 8 days citric acid fermentation on a molasses media by Aspergillus niger in flasks was 30-32oC.

Glushchenko et al. (1981) reported that production of citric acid by Aspergillus niger depended upon concentration of molasses in the medium. The growth yield biomass and the concentration of citric acid in the medium showed periodic changes during fermentation when sugar concentration was maintained at 13.5 percent.