CONTINUOUS METHOD OF PRODUCING CITRIC ACID AND ITS SALTS Russian patent published in 1999 - IPC

FIELD: biotechnology, microbiological and food industries. SUBSTANCE: citric acid is produced by fermentation of fungus Aspergillus niger VKPM F-718 on molasses nutrient medium for two stages. On the first stage molasses is used at pH 4.0-5.0 and fermentation is carried out at 32-34 C. Then in 30-48 h process involves continuous feeding molasses solution and nutrient salts at dilution rate 0.025-0.03 h^-1. On the second stage method involves utilization of microorganism suspension overflowing from the first stage and a process is carried out at 30-32 C and at pH 2.0-3.0. Microorganism suspension is removed at the same rate. Mother liquors forming at citric acid crystallization are used for additional producing citric acid salts. For preparing the sowing material fungus mycelium A. niger F-718 is grown additionally for 16-20 h at 32-35 C and at pH 4-5 on molasses nutrient medium. EFFECT: intensified process, improved utilization of mother liquors at crystallization stage. 3 cl, 3 tbl