Semicontinuous culture

Owl 102644.2132 at compuserve.com
Mon Aug 24 18:31:07 EST 1998

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.


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