A comparative study on citric acid production kinetics of two Yarrowia lipolytica strains in two different media

Microbial production of citric acid was performed by Yarrowia lipolytica NBRC 1658 and a domestic strain in the media containing glucose or fructose as substrates. The study was carried out in a batch system. The non-competitive substrate inhibition model was proposed for growth of the yeasts in both substrate media. Higher dry mass and lower Ks values were obtained in glucose media when compared to fructose media. The highest citric acid concentration (65.1 g/L) was obtained with the domestic strain in the medium containing 200 g/L fructose. In the media containing fructose, maximum citric acid concentration and productivity values determined with the domestic strain were aproximately two-fold greater than those obtained with NBRC 1658 strain. The required initial concentration of glucose or fructose at which best citric acid production properties were observed changed between 100-200 g/L for both of the strains. The ratio of citric acid to isocitric acid was found to change between 11.70-16.62.