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Published on: December 15, 2017
General characteristics of optimal feed rate profiles for various fed-batch fermentation processes
J M Modak1, H C Lim, Y J Tayeb
1School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907.
Biotechnology and Bioengineering
|September 1, 1986
Summary
Optimal feed rate profiles for fed-batch fermentation were determined using singular control analysis. The study identifies key control sequences that maximize product yield or balance yield with fermentation time.
Area of Science:
- Biochemical Engineering
- Process Control
- Biotechnology
Background:
- Fed-batch fermentation is a critical bioprocess for producing valuable compounds.
- Optimizing feed rate profiles is essential for maximizing productivity and yield.
- Previous methods often lack a systematic approach for determining optimal feed strategies.
Purpose of the Study:
- To deduce general characteristics of optimal feed rate profiles for fed-batch fermentation.
- To analyze the impact of singular controls and arcs on process optimization.
- To provide a framework for determining optimal control sequences based on growth and product formation rates.
Main Methods:
- Analysis of singular controls and singular arcs in fed-batch fermentation models.
- Mathematical modeling based on four mass balance equations.
- Identification of optimal control sequences including maximum feed rate, batch periods, and singular feed rate periods.
Main Results:
- The most general optimal control sequence comprises distinct periods: maximum feed rate, batch, singular feed rate, and batch.
- Degenerate sequences can occur depending on initial conditions.
- Singular control maximizes product yield when fermentation time is not critical; it balances yield and growth rate when time is important.
Conclusions:
- Optimal feed rate profiles are dependent on specific growth and product formation kinetics and initial conditions.
- The determined optimal control sequences provide a systematic method for enhancing fed-batch fermentation efficiency.
- Determining switching times for the identified control sequence is the key to implementing optimal feed rate profiles.
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