M. Taniguchi et al., ETHANOL-PRODUCTION FROM A MIXTURE OF GLUCOSE AND XYLOSE BY A NOVEL COCULTURE SYSTEM WITH 2 FERMENTERS AND 2 MICROFILTRATION MODULES, Journal of fermentation and bioengineering, 84(1), 1997, pp. 59-64
We developed a novel co-culture system composed of two fermenters and
two microfiltration modules for efficient ethanol production from a mi
xture of glucose and xylose by co-culture of Pichia stipitis and Sacch
aromyces cerevisiae, In a conventional co-culture where P. stipitis an
d S. cerevisiae were inoculated simultaneously into a single fermenter
, it was impossible to maintain the specific oxygen uptake rate (qO(2)
) at an optimum value for ethanol production from xylose by P. stipiti
s due to oxygen consumption by S. cerevisiae. The ethanol concentratio
n obtained in the conventional co-culture was lower than that in a sin
gle culture of P. stipitis alone in which qO(2) was adjusted to an opt
imum level depending upon the kind of sugar consumed. The proposed co-
culture system allowed regulation of the dissolved oxygen concentratio
n at a level suitable for an individual yeast in each fermentor as wel
l as the successful exchange of culture medium between two fermenters.
When P. stipitis and S. cerevisiae were cultivated individually under
different oxygen supply conditions in the new co-culture system, the
yield and productivity of ethanol from a glucose and xylose mixture we
re higher than in single culture of P. stipitis alone.