Polyhydroxyalkanoate Production from Eucalyptus Bark's Enzymatic Hydrolysate.

Area of Science:

• Biotechnology
• Polymer Science
• Sustainable Materials

Background:

• Polyhydroxyalkanoates (PHAs) are biodegradable polymers with potential to replace fossil-based plastics.
• High production costs, linked to cultivation media, hinder widespread PHA adoption.
• Eucalyptus globulus residues represent an abundant, low-cost, and sustainable carbon source.

Purpose of the Study:

• To evaluate eucalyptus bark hydrolysate as a sole carbon source for bacterial PHA production.
• To explore the potential of forestry waste in a circular bioeconomy for bioplastics.
• To assess PHA production by different bacterial strains using this novel feedstock.

Main Methods:

• Enzymatic saccharification of eucalyptus bark using Cellic® CTec3 to obtain a sugar-rich hydrolysate.
• Bacterial cultivation in bioreactors using eucalyptus bark hydrolysate as the sole carbon source.
• Analysis of bacterial growth rates and PHA composition (e.g., mcl-PHA, PHB).

Main Results:

• Several bacterial strains, including *Pseudomonas citronellolis* and *Burkholderia thailandensis*, utilized eucalyptus hydrolysate for PHA production.
• *Pseudomonas citronellolis* showed high growth but low mcl-PHA accumulation.
• *Burkholderia thailandensis* and a *Pseudomonas* sp. isolate achieved higher PHA accumulation, with the latter reaching 31 wt.% PHB under nitrogen limitation.

Conclusions:

• Eucalyptus bark enzymatic hydrolysate is a viable feedstock for PHA production.
• This approach offers a sustainable route to bioplastics from forestry waste.
• Further research can optimize conditions for cost-effective and high-yield PHA synthesis.