Exam questions

for the course Bioengineering Methods

spring semester of the academic year 2016/2017 (text marked in red will not be part of the exam) (PDF version)

Syllabus | Evaluation system | Exam questions | Study materials

  1. Enzyme catalysis: principle of catalytic action of enzymes, rate of enzyme reactions and e. activity, Michaelis-Menten kinetics (derivation assuming quasi-steady-state or quasi-equilibrium). Other cases of enzyme kinetics. Determination of kinetic coefficients of enzyme reactions.
  2. Enzyme reaction with M-M kinetics in a batch reactor, CSTR and plug-flow tubular reactor. Substrate inhibited enzyme reaction in a CSTR.
  3. Inactivation of enzymes, inactivation in an isothermal batch reactor.
  4. Inactivation in a plug-flow tubular reactor with heat removal, tubular reactor with axial dispersion.
  5. Transport phenomena in systems with immobilized enzymes. Immobilization techniques. External mass transfer  in nonporous particles with immobilized enzyme. Dimensionless formulation, external effectiveness factor.
  6. Internal mass transfer in porous (spherical) particles with immobilized enzyme,  effective diffusivity, hindrance factor, diffusion time. Mass balance of substrate in porous spherical particle with diffusion and enzyme reaction, internal effectiveness factor.
  7. Dimensionless formulation of the diffusion and reaction in a porous particle with immobilized enzyme obeying Michaelis-Menten kinetics.  Qualitative dependence of the effectiveness factor on Thiele modulus. Limit cases of the M-M kinetics ( zero- and first-order kinetics).  Combination of external mass transfer with internal reaction and diffusion, Biot number.
  8. Growth of microbial cells, transport of molecules across cell membrane. Growth yield, other yield coefficients, maintenance metabolism.
  9. Stoichiomety of cell growth and product formation. Elemental balances, degree of reduction and electron balancing, relation between empirical stoichometric equation and yield coefficients. Heat yield, reaction enthalpy and enthalpy balance.
  10. Growth curve in batch system and its phases. Ustructured models of growth in batch reactor. Logistic equation, Monod kinetics, mass transfer effects. Specific rate of product formation. Growth of biomass in the presence of two substrates.
  11. Structured models of growth. Williams compartmental model.
  12. Growth in continuous bioreactors,  description of chemostat, wash out phenomenon. Optimal biomass productivity. Balance of biomass, substrate and product when maintenance and product formation is present.
  13. Modifying batch and continuous reactors: Multistage chemostat. Chemostat with recycle
  14. Fed-batch operation, immobilized cells.
  15. Mixed microbial cultures, classification of interactions. Models of competition, mutualism and predation. Industrial utilization of mixed cultures.