Polyhydroxyalkanoate production by engineered Halomonas grown in lignocellulose hydrolysate

Area of Science:

• Biotechnology
• Microbial Engineering
• Bioplastics Production

Background:

• Lignocellulose is abundant biomass, a potential alternative to glucose for microbial fermentation.
• Halomonas bluephagenesis is promising for polyhydroxyalkanoates (PHA) production, but its use of lignocellulose hydrolysate is underexplored.

Purpose of the Study:

• To engineer Halomonas bluephagenesis for efficient production of polyhydroxybutyrate (PHB) using lignocellulose hydrolysate.
• To investigate the utilization of xylose and lignocellulose hydrolysate by engineered H. bluephagenesis strains.

Main Methods:

• Established and compared four xylose metabolism pathways in H. bluephagenesis.
• Integrated xylA and xfp genes into the H. bluephagenesis genome.
• Cultured engineered strains in lignocellulose hydrolysate and assessed PHA production.

Main Results:

• Engineered H. bluephagenesis T39 produced 15 g/L CDW with 76 wt% PHB in lignocellulose hydrolysate.
• Scale-up in a 7 L bioreactor yielded 62 g/L CDW with 67 wt% PHB.
• Strain T43 synthesized P(3HB-4HB-3HV) copolymers from lignocellulose hydrolysate.

Conclusions:

• H. bluephagenesis can be engineered to efficiently utilize lignocellulose hydrolysate for PHB production.
• Co-utilization of glucose and xylose enhances biomass and PHA accumulation.
• Engineered strains offer a sustainable route for bioplastics production from biomass.