Chapter 2 Mode of operation in bio reactor Ch 03 B.pptx

Biochemical engineering

1. Enzyme Catalysis, Bioreactor and its Types A kinetic approach BTY-305 + CHE-428 18-09-2024

2. Types of Fermentation Alcoholic Fermentation : Used by yeast to produce ethanol and carbon dioxide, which is important in brewing, winemaking, and biofuel production. Lactic Acid Fermentation : Used by lactic acid bacteria to produce lactic acid, as seen in yogurt and cheese production. Acetic Acid Fermentation : Used by Acetobacter to produce acetic acid in vinegar production. Applications : Fermentation is used in various industries, including food and beverage production, pharmaceuticals (for antibiotic and enzyme production), biofuels, and more.

3. Mechanism of Enzyme Catalysis

4. Michaelis-Menten Model For enzyme-catalyzed reactions, the Michaelis-Menten equation is often used to describe the kinetics of the reaction. It assumes that the formation of an enzyme-substrate complex (ES) is in a quasi-steady state. The basic Michaelis-Menten equation is: 𝑣=𝑉 max [𝑆] 𝐾 𝑚 +[𝑆] Where: v is the reaction rate (velocity). V max ​ is the maximum reaction rate, achieved when the enzyme is saturated with substrate. [S]is the substrate concentration. K m ​ is the Michaelis constant, which represents the substrate concentration at which the reaction rate is half of Vmax​. Enzyme Kinetics

5. Key assumptions : The enzyme concentration is constant. The substrate concentration is significantly higher than the enzyme concentration. Formation of the enzyme-substrate complex is much faster than product formation.

6. Cell Growth Kinetics, Monod Kinetics For microbial reactions, such as fermentation or bioprocessing with cell cultures, the reaction rate is often modeled in terms of cell growth, substrate consumption, and product formation. The Monod equation describes the relationship between the specific growth rate of microorganisms and the substrate concentration, analogous to Michaelis-Menten kinetics for enzymes: Where: μ is the specific growth rate of the microorganism (h⁻¹). μ max ​ is the maximum specific growth rate. [S]is the substrate concentration. K s ​ is the half-saturation constant (the substrate concentration at which the growth rate is half its maximum value). This model is used for predicting microbial growth in batch or continuous cultures. At low substrate concentrations, the growth rate depends on substrate availability, while at high concentrations, the rate reaches a maximum value.

7. Conversion Time:  A ll rates describe a process occurring over some amount of time, the rate of a chemical reaction is in units of (change in reactant or product)/(time elapsed). If we measure the amount of a chemical in grams, and the time in seconds, the rate has units of grams/second, or g/s. R--------------------------------------------P

8. Mass Balance Approach:

9. Conversion Time Equation for a Batch Process

10. Zero Order

11. Conversion time (T) is…………….

12. First Order Reaction

13. Order of Reaction Either the differential rate law or the integrated rate law  can be used to determine the reaction order from experimental data. Often, the exponents in the rate law are the positive integers: 1 and 2 or even 0. Thus the reactions are zeroth, first, or second order in each reactant

14. Bioreactors can be categorized based on their modes of operation, which determine how they function and interact with the materials being processed. Here are some common types based on modes of operation: Batch Bioreactor Continuous Bioreactor Fed-Batch Bioreactor Perfusion Bioreactor Plug Flow Bioreactor Reverse Flow Bioreactor

15. Reactants (feed stock, inoculum, media/enzymes) are loaded into the reactor. Reaction conditions are set for the given time period and reactor sealed. After the given time period the products are harvested Uses –Pharmaceuticals, food, Cosmetics Advantages : Low contamination and easy operation Disadvantages: Production stopped during product recovery and sterilization . Batch Bioreactor

16. The Importance of μ max For processes where maximal growth rates are desirable, attainment of μ max in culture is important. Since μ max is determined by the genetics of the microorganism conditions of culture Attainment of μ max has implications for both determinants. For other processes, identification of μ max is important so that it can be avoided e.g. in the production of secondary metabolites.

17. CONTINUOUS BIO-REACTOR Substrate conc. and other conditions remain constant, and the cell grow at a constant, fully acclimatized exponential rate on the effluent Defining characteristics of the continuous culture is a perpetual feeding process The reaction variables and control parameters remain consistent, establishing a time – constant state with in the reactor

18. 2) Continuous Bioreactor Continuously added reactants by adding fresh nutrients or substrate while simultaneously removing spent media or products. This mode allows for a steady-state condition and is beneficial for large-scale production, ensuring a constant supply of nutrients and a continuous removal of waste products. Uses –in industries where consistent output is crucial. Advantages Higher rate of production It is possible to maintain this reactor at isothermal conditions for high heat of reaction.  It is quite easy to maintain good temperature control with this reactor.  Due to large volume, it provides a long residence time.  It also has simplicity of construction.  Easy to clean  Low operating (labor) cost Disadvantages: Higher chances of contamination Conversion of these reactors is low due to this they are not preferred. These reactors are not suited for high heat effect since availability of both heat transfer coefficient and heat transfer per unit area is low.

19. Substrate is initially present at a higher concentration i.e. (S) > Ks, hence equation µ = µ max  S/ K s  + S is approximately 1. S/ Ks + S = 1 Thus, µ = µ max. When substrate concentration is low, as usually occurs at end of growth phase, then, S/ Ks + S < 1 Hence, µ < µ max. BATCH BIO-REACTOR

20. Actual growth rate depends not only on the volumetric flow rate of the medium into the reactor, but also on the dilution rate (D) D=F/V Net change in the cell conc. Over a period of time may be expressed as dX/dt = rate of growth in reactor- rate of loss from reactor (µX-Dx) Under the steady state conditions, the rate of growth = rate of loss dX/dt = 0 Therefore, µX = DX & µ = D

21. For any given dilution rate, under steady state condition, the residual substrate conc. in the reactor can be predicted by substituting D for µ in the monad equation D = µ max  S r / K s  + S r Where, S r = steady state residual substrate conc. In the reactor at the fixed dilution rate. Rearrangement gives, D(K s  + S r ) = µ max  S r OR DK s  + D S r = µ max  S r Dividing by s gives, DK s  / S r + D = µ max Hence, S r = DK s / µ max - D

22. 3) Fed Batch Bioreactor Intervalley added reactants or substrate with products removal intermittently or at the end. Usually 20% of the reactor is filled initially and rest is filled intervalley. Uses –in industries where certain concentration of product is inhibitory to the reaction e.g 16%C2H5OOH is inhibitory to the production of acetic acid. Advantages & Disadvantages: Same as batch process

23. FED BATCH BIO-REACTOR

24. 4) Perfusion Bioreactors: These operate by continuously replacing the media while retaining the cells or microorganisms within the bioreactor. Perfusion allows for continuous cell culture and is commonly used in pharmaceutical and biotech industries for the production of proteins, antibodies, and other biologics. 5) Plug Flow Bioreactors: Also known as tubular reactors, these maintain a continuous flow of substrate along the length of a tube or channel where microorganisms or catalysts facilitate the desired reactions. Plug flow reactors are efficient for reactions requiring precise control over residence time and can be used in various chemical and biological processes. 6) Reverse Flow Bioreactors: These operate by continuously changing the flow direction of the media within the reactor. This mode helps improve mixing and mass transfer rates, making it suitable for certain applications where enhanced mixing is critical .

25. Absolute Factors Nutrients pH Temperature Oxygen Rate-Determining Factors Temperature pH Mass Transfer Energy Transfer Factors Determining Growth & Synthesis of Product synthesis of Products