Citric acid production from sucrose by single and mixed cultures of Y. lipolytica immobilized in carrageenan gels beads were investigated in repeated batch culture. The best results were obtained for 2% carrageenan gel beads containing 15% of biomass. The use of gels treated with glutaraldehyde containing mixed cultures of Suc^- and Suc⁺ (both in ratio 2:1 and 3:1) gave the highest level of citric acid during the fifth 7-day batch. The repeated batch cultures with free cells were more efficiency than with immobilized cells, because achieved both higher citric acid concentration and yield.

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