Chemical Reaction Engineering (CRE) is the field that studies the rates and mechanisms of chemical reactions and the design of the reactors in which they take place. Lecture 16

Web Lecture 16 Class Lecture 25 – Thursday 4/14/2011 Bioreactors Monod Equation Yield Coefficients Washout 2

A given enzyme can only catalyze only one reaction. Urea is decomposed by the enzyme urease, as shown below. Michaelis Menten Equation The corresponding mechanism is: 3

Nutrient (S) + + Products cells more cells 4

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inoculum t=0 time  8 Cells + Substrate  More Cells + Product

9 Exponential Growth Phase Death Phase Stationar y Phase Lag Phase 0 time lnC c a)Phases of Bacteria growth: I. Lag II. Exponential III. StationaryIV. Death b) Monod growth rate law:

10 Accumulation = [In] - [Out] + [Growth] - [Death]

Rate Laws: C p *= Product Concentration at which all metabolism ceases 11

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13 Can’t separate substrate consumption used for cell growth from that used for product formations during exponenial growth.

v 0 C S0 V=V 0 vCCCSvCCCSC Volume=V 14 1) Mass balance:

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2) Rates: 3) Parameters: 16

1.) d(C C )/d(t)=-D*C C +(r g -r d ) 2.) d(C S )/d(t)=-D*(C S0 -C S )-Y sg *r g -m*C C 3.) d(C P )/d(t)=-D*C P +Y PC *r g 4.) rg=(((1-(C P /C pstar ))**0.52)*mumax*(C S /(K S +C S ))*C C 5.) D=0.2 6.) k d = ) r d =k d *C C 8.) C S0 =250 9.) Y PC = ) m= ) mumax= ) Y SC = ) K S =1.7 17

1. Steady State - Neglect Death Rate and Cell Maintenance 2. Cell 18

3. Substrate 19

CSTR Washout C DWDW DC 20 Washout dilution rate

How does this figure relate to drinking a lot of fluids when you have an infection or cold? DC C DWDW D D maxprod 21

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