Lecture 3 bioprocess control

1. 14 th . July 2010 CEPP, UTM Skudai , Johor Prof. Dr. Hesham A. El Enshasy Faculty of Chemical Engineering CEPP, UTM, Skudai , Malaysia Bioprocess Control (On-line, off-line and in-line)

2. Parameters for measurements and control for cultivation system Cell Input and Cell out-put (conditions and nutrients requirements) Sensors used for bioreactors Main Items of Presentation Feed back loops for bioprocess control Summary screen for different control system SCADA system for control using ethernet platform

3. Cell In-put and Cell Out-put

4. CELL Oxygen Carbon and Energy Sources Nitrogen Source Other requirements (P, S,Na,K,Mg,etc …) Carbon dioxide Biomass Metabolite(s) Water Heat Substrate(s) Input and Output

5. Physical Chemical Biological Temperature Bioreactor Pressure (St. St. Bioreactors) Agitation Speed Gas Flow rate Total volume Feeding rate Power Input Foam pH Dissolved oxygen Cell Morphology Cell viability Optical Density Cell Dry weight Cellular composition Specific growth rate Specific substrate(s) consumption rates. Specific production rate Reactor weight Feeding tank weight Culture Viscosity Gas Hold up Gas Mixing pattern Dissolved carbon dioxide Redox potential Out gas analysis (O 2, CO 2 , N 2 ) Substrate(s) Product(s) Enzyme activities Volatile compounds Conductivity Biomass composition (C,H,O,N,P,S) Metabolite profiling Mineral Ions Oxygen uptake rate Carbon dioxide production rate RQ Growth inhibitors Protein DNA / RNA ATP / ADP / AMP Different Parameters for cultivation system

6. Integrated of Mathematical Methods for Advanced Process Control Ref. (Clementschitsch and Bayer. Microbial Cell Factories 5:19 (2006)

7. Input and Output of Bioreactor system (General overview)

8. Main in situ sensors used for measuring cultivation parameters Culture parameters Sensor Range Accuracy Temperature Pt-100 0-150 C 0.1 C Pressure Piezoresistor 0-2 bar 20 mbar Gas flow Thermal mass flow meter Upto 2 v v -1 min Based on bioreactor volume 0.1% pH pH electrode 2-12 0.02 pO 2 Polarografic electrode 0-400 mbar 2 mbar pCO 2 Membrane covered pH electrode 0-100 mbar 2 mbar

9. Feed pump(s) Temperature Aeration Power consumption Stirrer Speed Exhaust gas Analyzer pH DO Pressure Weight / volume Measurement and open or closed loop control Measurement only Common measurement and control of bioreactors as generally accepted as routine equipment

10. Lower ports for in situ sterilizable STR

11. Application measurement Lower ports Upper ports Headplate ports Temp./pH/DO/ DCO 2 / Turbidity probes/substrate (s) on-line + (for pilot scale bioreactors) - + (only for small scale bioreactors / Glass bioreactors) Pressure gauge or Pressure sensor - - + Line to outgas analysis - - + (after condenser and out-gas fileter ) Feeding / acid-based / Antifoam addition - Highly suitable (Small scale pilot) Less Suitable (Large scale) Highly suitable (Large scale) Less Suitable (Small scale pilot) Harvest (Continuous Culture) (Repeated batch) + - - Sampling + - - Upper/lower ports and Headplate

12. pH values of different liquids

13. pH and hydrogen ion concentration

14. pH measuring circuit and pH meter construction

15. Temperature Effect on pH value

16. Temperature Error Table

17. DO meter construction

18. The relation between DO and Temperature

19. Standard Antifoam Sensor Foam sensors: Low foam sensor High foam sensor Type of foam: Early foaming Late foaming Antifoam effects on: DO Growth morphology (Filamentous MO)

20. On-line cell mass determination methods Principle Advantages Disadvantages Optical density Wide linear range Some interference Culture fluorescence Measurement of cellular activity Singanal interpretation is difficult Capacitance Wide measurement range Measurement of cellular activity Interferance from aeration and aeration Signal interpretation is difficult Ultrasonic Wide linear range Self cleaning Interference from aeration and agitation Temperature sensitive

21. On-line cell mass and viability measurement Theory: Cells with intact plama membranes act like tiny capacitors under the influence of electric field. The nonconducting nature of plasma membranes allows charge to build up. The resulting capacitance can be measured and is usually expressed in picofarad per centimeter (pF/cm). It depends on the cell type and is directly proportional to membrane bound volume of viable cells.

22. Stat-culture Sensor Controlled variables pH-Stat pH electrode (online) Acid-based DO-Stat DO electrode (online) Aeration Agitation Oxygen (optional) Nutri-Stat (Chemo-Stat) nutrient sensor (on-line), Off-line analyzer (online), FIA (online) Feeding substrate (s) Turbidistat Turbidity meter (online) Feeding substrate(s) Harvest pump QO 2 and QCO 2 Stat Out-gas analyzer (in-line) Aeration Agitation Oxygen (Optional) Feeding substrate(s) Controlling stat-culture

23. Feedback control: A control algorithm to reduce the error between the set point and the controlled variable (most often PID or model predictive controller algorithm is used) Feedforward control: A computation of the manipulated variable from a measurement of the disturbance (most often corrected by a PID or model predictive controller) Feedback and Feedforward controllers

24. Basic feedback loops for a fungal culture for antibiotic production

25. Basic feedback loops for microbial high cell density formation

26. Bioreactor Input and Output for basic PID control feed

27. Connections to USB, controller software and Ethernet for SCADA

28. Supervisory Control and Data Acquisition syste (SCADA)

29. Thank You