Ps. Meyer et Jc. Dupreez, EFFECT OF CULTURE CONDITIONS ON ASTAXANTHIN PRODUCTION BY A MUTANT OFPHAFFIA-RHODOZYMA IN BATCH AND CHEMOSTAT CULTURE, Applied microbiology and biotechnology, 40(6), 1994, pp. 780-785
Temperature and pH had only a slight effect on the astaxanthin content
of a Phaffia rhodozyma mutant, but influenced the maximum specific gr
owth rate and cell yield profoundly. The optimum conditions for astaxa
nthin production were 22 degrees C at pH 5.0 with a low concentration
of carbon source. Astaxanthin production was growth-associated, and th
e volumetric astaxanthin concentration gradually decreased after deple
tion of the carbon source. The biomass concentration decreased rapidly
during the stationary growth phase with a concomitant increase in the
cellular content of astaxanthin. Sucrose hydrolysis exceeded the assi
milation rates of D-glucose and D-fructose and these sugars accumulate
d during batch cultivation. D-Glucose initially delayed D-fructose upt
ake, but D-fructose utilization commenced before glucose depletion. In
continuous culture, the highest astaxanthin content was obtained at t
he lowest dilution rate of 0.043 h(-1). The cell yield reached a maxim
um of 0.48 g cells g(-1) glucose utilized between dilution rates of 0.
05 h(-1) and 0.07 h(-1) and decreased markedly at higher dilution rate
s.