eng Science and Education Publishing American Journal of Food and Nutrition 2014-06-30 2 3 43 48 10.12691/ajfn-2-3-2 AJFN2014232 article Abonama O. M. 1 Hoda Mahrous hmahrous7@yahoo.com 1 El baz A. F. 1 Hamza H. A 2 Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute (GEBRI), University of Sadat City Department of Microbial Biotechnology, Genetic Engineering and Biotechnology Research Institute (GEBRI), University of Sadat City Citric acid is one of the most versatile industrial organic acids that are used in food industries, cosmetics and pharmaceuticals products. This work aimed to produce citric acid by Candida lipolytica under submerged fermentation conditions using a Plackett-Burman design. Twelve factors including pH, concentration of sodium acetate, magnesium sulfate, Ammonium chloride, potassium phosphate, ferric sulfate, manganese sulfate, zinc sulfate, yeast extract, glucose, aeration ratio and incubation time at a temperature of 30°C were tested as main variables affecting citric acid production using Plackett-Burman design. The results indicated that pH (7), concentration of sodium acetate (10g/L), magnesium sulfate (1.5g/L), potassium phosphate (5g/L), ammonium chloride (3g/L), ferric sulfate(140mg/L), manganese sulfate (50 mg/L), zinc sulfate (80 mg/L), yeast extract (5g/L), glucose (150g/L), aeration ratio(75ml medium/ flask250ml) and incubation period of 7 days were the most effective factors for the highest yield of citric acid production. The highest citric acid concentration was 22.8 g/L of the medium under the previously mentioned conditions. http://pubs.sciepub.com/ajfn/2/3/2/ajfn-2-3-2.pdf Citric acid- Candida lipolytica-Plackett-Burman design