Continuous Cultivation - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 607

CHAPTER
12

Co ntinuous Cultivat ion

OUTLINE

12.1. Continuous Culture 608 12.4. Immobilized Cell Systems 641

12.1.1. Chemostat Devices for
Continuous Culture

12.4.1. Active Immobilization
of Cells

608 642

12.1.2. The Ideal Chemostat 610 12.4.2. Passive Immobilization:

Biological Films 12.1.3. The Chemostat as a Tool 619 645

12.2. Choosing the Cultivation Method 620
12.2.1. Chemostat with Recycle

12.5. Solid Substrate Fermentations 648

623

12.6. Summary 650

12.2.2. Multistage Chemostat
Systems

626 Problems 652

12.3. Wastewater Treatment Process 634

Cell growth and/or fermentation in different conditions can render significantly different
rate for the production of the desired primary product. Difference in trace elements/electro-
lytes can alter the growth and fermentation pattern. Macronutrient concentration changes
affect the rates in a more measurable manner. In some cases, we have limitations on the
type of reactor and/or operating strategies. In other cases, our limitation is only the highest
efficiency achievable. An important decision for selecting or designing any biological or
chemical process concerns the configuration the reactor system should take. The choice of
reactor and operating strategy determine product concentration, number and types of impu-
rities, degree of substrate conversion, yields, and whether sustainable, reliable performance
can be achieved. The reactor section represents a very major component (usually 40%) of

the total capital expenditures, which is comparable to separation needs. Choices at the
reactor level and of the biocatalyst determine the difficulty of the separation. Thus, our choice
of reactor must be made in the context of the total process: substrate, biocatalyst, reactor, and
separation and purification train. In Chapter 11, while we were discussing the kinetics of cell

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