Polyphosphate kinase deletion increases laboratory productivity in cyanobacteria

Area of Science:

• Cellular metabolism
• Cyanobacterial biotechnology

Background:

• Cellular energy regulation is key to photosynthetic organism productivity.
• Polyphosphate metabolism's role in energy management (ATP storage/dissipation) is under investigation.

Purpose of the Study:

• To test if polyphosphate synthesis/degradation impacts energy management and ATP levels.
• To assess the effect of polyphosphate kinase deletion on cyanobacterial growth and productivity.

Main Methods:

• Generated a polyphosphate kinase (ppk) knock-out mutant in Synechocystis sp. PCC 6803.
• Compared growth rates and ATP levels of the mutant and wildtype strains under varying carbon conditions.
• Assessed growth under stress conditions and ethylene production in a ppk deletion strain with heterologous ethylene-forming enzyme expression.

Main Results:

• The ppk knock-out mutant showed higher ATP levels and faster growth in high-carbon conditions compared to wildtype.
• The mutant exhibited a growth defect under multiple stress conditions.
• Combined ppk deletion and ethylene-forming enzyme expression led to higher ethylene productivity.

Conclusions:

• Polyphosphate synthesis and degradation function as an energy regulation mechanism.
• Targeting these mechanisms could enhance productivity in photosynthetic organisms.
• Polyphosphate pathways may be valuable targets for biocontainment strategies.