Biomedical Engineering Reference
In-Depth Information
in filter pouches that can be physically removed from the bioreactors after
equilibration and directly transferred into columns. Suddenly, there is a
unit process that replaces three processes. One can even go further and use
the flexible bag as the first purification column. These innovations are in the
offing and are a subject of several U.S. patents filed by MayaBio Company
(
www.mayabio.com
).
The use of bioreactors for bacterial cultures poses another set of chal-
lenges that will eventually be resolved, wherein chemical methods will
be used to disrupt bacteria in the culture medium, additional chemi-
cal means to unfold the inclusion bodies and refold proteins, all in the
same bag where the fermentation process takes place. In the end, a resin
capable of capturing partially folded or unfolded protein will be used to
separate the target protein, discarding the balance of the mixture in the
disposable bag.
Biosafety
The industry has historically taken a very cautious approach toward the dis-
posal of GMOs and many of them overbuilt their facilities to decontami-
nate objects. In those cases where the GMOs fall in the exempt category of
biosafety, such as recombinant CHO cells, these may be discharged in the
municipal sewer systems. In the past, the industry became overconcerned
about releasing recombinant agents into the atmosphere, but if an entity is
not infectious or is unable to survive outside of a specific environment, these
fall under an exempt qualification as described in Appendices C and K of
the NIH biosafety guidelines. However, the manufacturers must also consult
with local requirements of biosafety compliance and find out if GLSP guide-
lines apply to them or not.
Autoclaves
Autoclaves will not be needed: the GMO contact surfaces and effluents
can all be decontaminated by chemical means. Autoclaves are also used
to sterilize multiuse products, media, buffers, connectors, and other items
that come in contact with the product; the use of disposable systems makes
them redundant. The autoclave is the single most energy-consuming and
energy-dissipating item using high-quality water in very large quantities.
The heat dissipated by an autoclave upsets the balance of HVAC calcula-
tions and the facilities need to be sized to accommodate frequent use of
