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A hidden square-root boundary between growth rate and biomass yield
Wilson W Wong1, Linh M Tran, James C Liao
1Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA.
Biotechnology and Bioengineering
|August 7, 2008
Summary
Growth rate in cells is limited by a hidden boundary, determined by biomass yield and enzyme kinetics. This finding provides an upper limit for cell growth, aiding in strain design for product formation.
Area of Science:
- Biotechnology
- Metabolic Engineering
- Enzyme Kinetics
Background:
- Biomass yield is calculable from metabolic networks, but growth rate prediction remains challenging.
- Growth rate and yield can vary independently, lacking a clear predictive relationship.
Purpose of the Study:
- To uncover a hidden boundary for cellular growth rate based on enzyme kinetics.
- To establish a predictive relationship between biomass yield and growth rate.
Main Methods:
- Analysis of established enzyme kinetics and physiological parameters.
- Mathematical modeling to derive a growth rate boundary equation.
- Validation with experimental data.
Main Results:
- A novel growth rate boundary was identified, dependent on the square-root of biomass yield, substrate turnover number, and maximum enzyme synthesis rate.
- Cells cannot exceed this calculated square-root boundary for growth.
- The derived relationship acts as an upper limit, not a direct predictor, of growth rate.
Conclusions:
- The identified growth rate boundary offers insights into cellular metabolism and limitations.
- This finding has implications for optimizing microbial strains in synthetic biology and biotechnology.
- Understanding this boundary can guide strain design for enhanced product formation.
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