Paracoccus kondratievae produces poly(3-hydroxybutyrate) under elevated temperature conditions

Area of Science:

• Microbiology
• Biotechnology
• Polymer Science

Background:

• Polyhydroxyalkanoates (PHAs) are biodegradable polymers with diverse applications.
• Identifying novel PHA-producing microorganisms is crucial for sustainable biopolymer production.
• Paracoccus species are known PHA producers, but their thermotolerant capabilities are less explored.

Purpose of the Study:

• To characterize the thermotolerant bacterium Paracoccus kondratievae for poly(3-hydroxybutyrate) (PHB) production.
• To compare PHB production dynamics with the related species Paracoccus denitrificans.
• To investigate optimal conditions and triggers for PHB accumulation in P. kondratievae.

Main Methods:

• Chemical and thermal characterization of bacterial isolates.
• Cultivation of P. kondratievae under varying temperatures and media compositions.
• Analysis of poly(3-hydroxybutyrate) (PHB) content and depolymerase enzyme activity.
• Assessment of PHB production in response to osmotic stress.

Main Results:

• Paracoccus kondratievae accumulates poly(3-hydroxybutyrate) (PHB) up to 46.8% of cell dry weight at 42°C.
• P. kondratievae exhibits significant differences in PHB production dynamics compared to P. denitrificans.
• Optimal PHB production occurred at 42-47°C, with peak accumulation at 24h in the stationary phase.
• Glycerol as a sole carbon source with a C:N ratio of 10 yielded the highest PHB levels.
• PHB production was induced by osmotic stress, and PhaZ depolymerase facilitated PHB decline.

Conclusions:

• Paracoccus kondratievae is a promising thermotolerant species for poly(3-hydroxybutyrate) (PHB) biosynthesis.
• Its ability to produce PHB at elevated temperatures and its distinct production dynamics offer advantages for industrial applications.
• Understanding the role of osmotic stress and depolymerase activity provides insights for optimizing biopolymer yields.