Engineering Halomonas bluephagenesis via small regulatory RNAs

Area of Science:

• Industrial Biotechnology
• Microbial Engineering
• Synthetic Biology

Background:

• Halomonas bluephagenesis is a robust microorganism suitable as a chassis for industrial biotechnology.
• Non-model organisms like H. bluephagenesis require efficient metabolic engineering tools.
• Fine-tuning metabolic fluxes is crucial for enhancing production phenotypes.

Purpose of the Study:

• To develop and characterize a novel gene expression regulation system in H. bluephagenesis.
• To enhance the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHB/HV).
• To establish a framework for utilizing small regulatory RNA (sRNA) systems beyond Escherichia coli.

Main Methods:

• Engineered a small regulatory RNA (sRNA) PrrF1 scaffold from Pseudomonas aeruginosa with a target-binding sequence.
• Utilized the cognate P. aeruginosa Hfq (HfqPa) to facilitate sRNA-mRNA hybridization.
• Applied the PrrF1-2-HfqPa system to target prpC, phaP1, and minD genes in H. bluephagenesis.
• Developed an sRNA library for large-scale target identification.

Main Results:

• The PrrF1-2-HfqPa system significantly increased the 3-hydroxyvalerate fraction in PHB/HV to 21 mol% from 3.1 mol%.
• Simultaneous repression of phaP1 and minD genes led to the formation of large polyhydroxybutyrate granules.
• The system demonstrated effectiveness in repressing gene expression without relying on E. coli-based systems.

Conclusions:

• The PrrF1-2-HfqPa system is a highly efficient tool for gene expression regulation in H. bluephagenesis.
• This sRNA-based system offers a powerful new avenue for metabolic engineering in non-model organisms.
• The study provides a versatile framework for exploiting diverse sRNA systems in genome engineering for industrial applications.