Natural and engineered hydroxyectoine production based on the Pseudomonas stutzeri ectABCD-ask gene cluster

Area of Science:

• Microbiology
• Biotechnology
• Biochemistry

Background:

• Hydroxyectoine is a compatible solute used for cellular protection.
• Understanding its biosynthesis is crucial for biotechnological applications.
• Pseudomonas stutzeri is a known bacterium with potential for ectoine production.

Purpose of the Study:

• To identify and characterize the hydroxyectoine biosynthesis gene cluster in Pseudomonas stutzeri DSM5190(T).
• To evaluate the potential of P. stutzeri DSM5190(T) for hydroxyectoine production.
• To achieve de novo production of hydroxyectoine in a heterologous host, Escherichia coli.

Main Methods:

• Identification and analysis of the ectABCD-ask gene cluster in P. stutzeri.
• Heterologous expression of the P. stutzeri gene cluster in E. coli.
• Cultivation of engineered E. coli under varying salinity conditions.
• Analysis of hydroxyectoine production rates and purity.

Main Results:

• A functional hydroxyectoine biosynthesis gene cluster (ectABCD-ask) was confirmed in P. stutzeri DSM5190(T).
• Heterologous expression in E. coli resulted in hydroxyectoine production controlled by native salt-induced promoters.
• E. coli exhibited a higher specific production rate compared to P. stutzeri.
• Effective hydroxyectoine production was achieved at low salinity (2%) with minimal co-solutes, simplifying downstream processing.

Conclusions:

• The identified gene cluster is functional and suitable for hydroxyectoine production.
• Heterologous production in E. coli offers a promising alternative for efficient hydroxyectoine synthesis.
• The ability to produce hydroxyectoine at low salinity with simple processing is a significant advancement.