The Bistable Behaviour of Pseudomonas putida KT2440 during PHA Depolymerization under Carbon Limitation

Area of Science:

• Microbiology
• Biotechnology
• Polymer Science

Background:

• Poly(hydroxyalkanoates) (PHAs) are biodegradable polyesters produced by bacteria.
• PHA metabolism is influenced by nutrient availability, with carbon excess favoring accumulation and carbon limitation triggering degradation.
• Understanding PHA dynamics in bacterial populations is crucial for optimizing bioplastic production.

Purpose of the Study:

• To investigate the single-cell population dynamics of Pseudomonas putida KT2440 during PHA polymerization and depolymerization.
• To elucidate the PHA distribution patterns during cell division under carbon-limited conditions.

Main Methods:

• Culturing Pseudomonas putida KT2440 under controlled physiological conditions (octanoic acid growth, then carbon limitation).
• Single-cell level analysis of population dynamics and PHA content.
• Observing PHA distribution during cell division.

Main Results:

• Pseudomonas putida KT2440 exhibits bistable behavior under carbon limitation.
• Cell division leads to the formation of two subpopulations: one with high PHA content and one with low PHA content.
• PHA distribution during cell division under carbon limitation is asymmetric, challenging previous assumptions.

Conclusions:

• PHA mobilization and distribution in Pseudomonas putida are more complex than previously thought.
• Asymmetric PHA segregation during cell division impacts population-level PHA dynamics.
• This finding has significant implications for the industrial production and application of biodegradable PHAs.