Dennis Bayrock wrote:
Your collegues are correct in regards to fed-batch
> fermentations- fresh medium is added (at a constant rate or step-rate
> increased) until the working volume is reached (at which point the
> fermentation becomes a continuous culture). There are also variations on the
> classical cascade fermentation where fresh medium is added as in fed batch-
> the fermentation is then called a fed-batch cascade fermentation.
> I hope this information helps!
Different laboratories (and industrial plants) use different terms.
What Yarlipo described is a process we freqently use, and call
"semi-continuous", sometimes with "intermittent feed" attached. What
we call "fed batch" is simply one cycle of this, with a final harvest
of broth when the full volume is reached. What you describe is what
we call a fed-batch beginning to a chemostat run. Continuous cultures
are divided into chemostats (which have continuous media fed in and
harvest drawn off), and perfusion runs (which include cell retention
or cell recycle).
I don't think there is much agreement on vocabulary between
different institutions. I've worked for 4 biotech companies as a
fermentation specialist, and they've all had different terms.