Poster
Presentation 28:
Oxygen transfer in viscous xanthan
gum fermentation broth:
A comparative study
Y.M. Lo and C.H. Hsu
Department of Animal and Food Sciences
Agriculture and Natural Resources
University of Delaware
531 S. College Ave
Newark, DE 19717
ymlo@udel.edu
(302) 831-1045
Oxygen transfer into viscous xanthan
fermentation broth in a
centrifugal, packed-bed bioreactor
(CPBR) is compared to the conventional
stirred-tank reactor with disc turbine
(STR-DT) or with marine propeller
(STR-MP), and the water-in-oil emulsion
system (STR-WIO). STR-WIO showed
the highest maximal volumetric transfer
coefficient (kLa) values,
while STR-MP had the lowest.
However, practical difficulties existed in
recovering xanthan polymers from such
an emulsion system. In CPBR it was
found that, at xanthan concentrations
at lower than 2%, maximum kLa values
were slightly lower than those of
STR-DT. On the other hand, when xanthan
concentration higher than 2%, maximum
kLa values in CPBR were
higher than those of STR-DT and close
to the values of STR-WIO system,
indicating improved oxygen transfer
in CPBR at high xanthan concentrations.
In addition, the recirculation stream
used to provide better mixing and
gas-liquid contact in CPBR had an
important role in providing aeration for
the gas-continuous CPBR system.
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