bioreaction and bioreactor n.
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  2. WHAT IS BIOREACTOR? • A special reactor that sustains and supports life for cells and tissue cultures. • Used in industrial processes to produce pharmaceuticals, vaccines, or antibodies • Bioreactors are commonly employed in the food and fermentation industries, in waste treatment, and in some biomedical operations - the heart of any industrial fermentation process. • The advantages are mild rxn conditions, high yields and stereospecificcompounds. • Bioreactors supply a homogeneous (same throughout) environment by constantly stirring the contents. • Bioreactors give the cells a controlled environment by ensuring the same temperature, pH, and oxygen levels.

  3. Bioreactor And Its Parts

  4. THE CELL • A cell uses its nutrients to produce energy and more cells. • The cell consists of a cell wall and an outer membrane that encloses cytoplasm containing a nuclear region and ribosomes. • The cell wall protects the cell from external influences. • The cell membrane provides for selective transport of materials into and out of the cell

  5. CELL GROWTH • The growth of an aerobic organism follows the equation; SUBSTRATE

  6. STAGES OF CELL GROWTH • Stages of cell growth in a batch reactor; Phase III: STATIONARY PHASE Cells reach a minimum biological place where the one or more of the nutrient are limiting. Phase I : LAG PHASE Little increase in cell conc’n. Cells are adjusting to their new environment, synthesizing enzymes, getting ready to reproduce. Phase IV: DEATH PHASE A decrease in live cell conc’n occurs. Phase II: EXPONENTIAL GROWTH PHASE. Cell divide at maximum rate, all of the enzyme’s pathways are in place.

  7. RATE LAWS Monod eqnfor exp growth.

  8. Growth rate, rg depends on the nutrient concentration (Cs)

  9. INHIBITION OF THE GROWTH RATE • In many systems, product inhibits the growth rate. (i.e.; Wine production)

  10. THE MOSER AND TESSIER • There are also Tessier & Moser eqns that fit experimental data better. • 𝜆 and k are empirical constants TESSIER MOSER

  11. Effect of Temperature can be given as

  12. STOICHIOMETRY • Stoichiometry for cell growth is complex, and varies with microorganism/nutrient system, and pH, T, etc. YIELD COEEFICIENT (Cell and substrate); • Product formation can take place during different phases of the cell growth cycle if it occurs during the exp growth phase:

  13. The stoichiometric yield coeff btw product & substrate is given by: • Another term is the maintenance utilization term: (to maintain a cell’s daily activities) • The rate of substrate consumption • Neglecting the cell maintenance

  14. Substrate Utilization If there is production during growth, it is difficult to separate amount of substrate used in production and growth The corresponding rate law is Growth associated product formation in the growth phase.

  15. Apparently, no net growth during stationary phase

  16. Mass balance There are two ways that we could account for the growth of microorganisms. Either no of living cells or mass of the living cells. For a CTSR: { called chemostats are the reactors that contain microorganisms}

  17. Substrate Balance For a Batch System: Cell balance Substrate

  18. DESIGN EQUATION For a CSTR The case where the volumetric flow rates in and out are the same and no live cells enter the chemostat DILUTION RATE The dilution rate is reciprocal of the space time,T

  19. CSTR mass balance; Using Monod Eqn;the growth rate,rg

  20. For steady state operation; Mass flow rate of cells out of the system,Fc Neglect death rate divide by CcV, The specific growth rate of the cell can be controlled by the dilution rate,D

  21. From Monod Eqn; If a single nutrient is limiting, - cell growth is the only process to substrate consumption. - cell maintenance is neglected.

  22. WASH OUT To learn the effect of increasing the dilution rate;Assume; the dilution rate at which wash-out will occur is:

  23. D for the maximum cell production: {Cell production per unit volume is the mass flow rate of cells out of the reactor} :

  24. THE END