W. Rymowicz et al., STUDIES ON CITRIC-ACID PRODUCTION WITH IMMOBILIZED YARROWIA-LIPOLYTICA IN REPEATED BATCH AND CONTINUOUS AIRLIFT BIOREACTORS, Applied microbiology and biotechnology, 39(1), 1993, pp. 1-4
Citric acid was produced from glucose in repeated-batch shake-flask an
d continuous air-lift cultivations by calcium-alginate-immobilized Yar
rowia lipolytica A-101 yeast. The medium composition was systematicall
y studied in a batch system by using experimental design and empiric m
odelling. The highest citric acid product concentration of 39 g/l was
reached with a medium containing 150 g/l of glucose, 0.105 g/l of pota
ssium dihydrogen phosphate, 0.84 g/l of magnesium sulphate and 21 mg/l
of copper sulphate (5.2 mg/l of copper). The results were further imp
roved by hardening the alginate carrier beads with glutaraldehyde, and
by activation of the immobilized biocatalyst in a nutrient solution.
Iii continuous air-lift bioreactors with varying height-to-diameter ra
tio the highest productivity of 350 mg/l per hour with a dilution rate
of 0.023 1/h and a citric acid product concentration of 12 g/l was re
ached with a ratio of 3.