NEW BRUNSWICK SCIENTIFIC BioFlo 415, Руководство по эксплуатации

Страница: 117 / 164

105
New Brunswick Scientific User’s Guide
16.7.1 Lag Phase
This initial phase is aptly named because it is the slow beginning of your
fermentation run, while the microbes become accustomed to their medium.
16.7.2 Exponential Growth Phase
After the initial lag, a sudden spurt in growth will indicate that the environment
is fully hospitable to the microbes. Compared to the nearly inanimate lag
phase, this activity will appear to be nearly uncontrolled.
16.7.3 Steady State Phase
Most of your run will be the desired steady state of growth. As long as the
temperature, pH, DO and other essential parameters are stable and you feed
your batch appropriately, this phase can last, for a standard e.coli fermentation,
for example, approximately 2-3 hours. Eventually, however, you must expect
your batch to decline.
16.7.4 Decline Phase
This final phase is marked by a slow dying off. It is, of course, inevitable.
16.8 Batch Operation
A batch operation is a closed growth environment in the sense that it contains a finite
amount of media. The inoculum grows through the various phases of fermentation
until it begins to decline and you harvest the desired product. It is easy to run and
yields results quickly.
16.9 Fed Batch Operation
A fed batch operation includes the addition of media to feed the batch fresh nutrient
and to dilute any build-up of toxic by-products in the broth, thereby extending the life
and growth of the desired product. Figure 63 on the following page is a simplified
depiction of this setup: