Bioreactor as fed-batch culture
Two fermentations were applied to produce PHAs by Ps. fluorescens S48
using pulsed and continuous feeding of oil. In the pulsed oil feeding, the amount
of WFO type 2 (10 ml-1
) was added to fermentation vessel. Two, three and four
additions of this amount of WFO were added during the first 12, 36 and 48 h of
cultivation period (fed-batch by pulsed feeding). In the second fermentation, the
WFO type 2 was fed continuously during the first 12, 18 and 24 h of cultivation
period at rates of 0.83, 0.55 and 0.42 ml-1
h
-1
, respectively (fed-batch by
continuous feeding). The final working volume in bioreactors was 1 liter at the
end of feeding period.
High-cell-density fed-batch culture
Three experiments of continuous fed-batch cultures were constructed to study
the effect of washed high-cell-densities of Ps. fluorescens S48 (0.36, 0.64 and
0.74 gl-1
) on PHAs production. WFO type 2 was fed continuously at 0.55 mll-1
h
-1
during the first 18 h of cultivation.