Other unstructured growth models slideshare
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This document discusses several unstructured kinetic models for microbial growth, including modified Monod models, Teisser's equation, Contois kinetics, multiple substrate Monod kinetics, double Monod kinetics, Monod diauxic growth, and product inhibition models. It provides examples of each model and in some cases parameter estimates obtained by fitting the models to experimental data describing the growth of various microorganisms.
Other unstructured growth models slideshare
- 1. OTHER UNSTRUCTURED MODELS Author: Guillermo Garibay Benítez University: Instituto Politécnico Nacional Mexico
- 2. • Monod modified form: • Shows initial concentration influence, which is sometimes observed if others components are growth limiting.
- 3. • Teisser equation • Relates μ with S in a exponential manner. • Gives same result as Monod model for low values of S since e-s/k ≈ 1 – s/KS para S → 0, but approximation to μm for large values of S is generally very fast.
- 4. • Contois equation: • Expresses saturation effective constant, this constant is proportional to biomass concentration. • At large values of X, μ is inversely proportional to X • It is used in occasions to represent a diffusive limitation in inmobilized biomass.
- 5. • Multiple substrate monod kinetics • Any substrate can be growth limiting, under conditions when another substrate is in excess. • Para S1=K1 y S2=K2, μ=μm/4 • An example is simultaneous requirement of glucose and oxigen by aerobic organisms.
- 6. Double Monod kinetics It can be described for two substrates acting like parallel reactions. Each substrate allows a different maximum specific growth rate It is used, for example, in the usage of alternative substrates like different types of sugars.
- 7. • Monod Diauxic growht • It can be modelled for two substrates • In this manner, S2 substrate uptake will be inhibited until S1 finishes, for low values of KI
- 9. • Inhibitory effect of lactic acid. Bibal et al (1988) studied the inhibiton of lactic acid on Streptococcus cremoris. • This influence was examined measuring specific growth rate during batch growth of the bacterium in media containing various concentrations of lactic acid (p). The results are summarized below: • It is mainly the dissociated form of lactic acid that passes through the cellular membrane, and we will therefore assume that it is only the undissociated acid that has a toxic effect on the cells. Plot the relative specific growth rate, i.e. µmax(p)/µmax(p=0), versus the concentration of undissociated acid concentration (in mM). pH = 6.3 was used and pKa for lactic acid is 3.88. Assume the first inhibition model mentioned above holds. Find the inhibition constant Ki. Plot the model with the experiments p (g /L) µ(h-1) 0 0.90 12 0.68 39 0.52 55 0.13
- 10. Continuation… • There seems to be a certain maximum concentration of undissociated acid above which growth stops. Try the next model to find the influence of pu on µ and estimate the model parameter. At what concentration of lactic acid will growth stop?
- 11. • An hybridome cell line is used for production of monoclonal antibodies. In a batch growth, the following data was obtained: Time (days) Cell concentration (cells mL-1x10-6) 0 0.45 0.2 0.52 0.5 0.65 1 0.81 1.5 1.22 2 1.77 2.5 2.13 3 3.55 3.5 4.02 4 3.77 4.5 2.2 Calculate specific growth rate during growth fase and duplication time
Editor's Notes
- #12: u=0.67 d-1 Td=ln2/u = 1 d