FDA-hydrolysis activity: A pre-screening tool for optimizing compost selection in standardized plastic biodegradation...

Area of Science:

• Environmental Microbiology
• Polymer Science
• Biotechnology

Background:

• Current plastic biodegradability standards (ISO 14855-1) use physicochemical parameters, which do not directly measure microbial activity essential for biodegradation.
• Selecting appropriate compost inocula is crucial for accurate biodegradation assessments.

Purpose of the Study:

• To evaluate fluorescein diacetate hydrolase (FDA-H) activity as a rapid biological indicator for pre-screening compost suitability for biodegradation testing.
• To compare FDA-H activity with existing microbial activity assays and assess its correlation with biodegradation rates.

Main Methods:

• Measured FDA-H activity in five compost samples.
• Correlated FDA-H activity with early CO2 evolution and final biodegradation rates of cellulose and polybutylene succinate (PBS).
• Utilized metagenomic analysis to investigate microbial succession during degradation.
• Compared FDA-H with respiration and dehydrogenase activity assays.

Main Results:

• FDA-H activity showed a strong positive correlation (r=0.93) with early CO2 evolution, indicating high initial microbial metabolic potential.
• Moderate correlations were found between FDA-H activity and final biodegradation rates of cellulose and PBS.
• Metagenomic analysis revealed distinct microbial succession patterns, particularly for synthetic polymers.
• FDA-H demonstrated advantages in speed and operational simplicity over other tested assays.

Conclusions:

• FDA-H activity serves as a valuable, rapid, and biologically relevant indicator for pre-screening compost suitability in biodegradation assessments.
• FDA-H complements, but does not replace, standardized biodegradation testing protocols like ISO/OECD.
• Integrating FDA-H can improve the efficiency, reliability, and biological relevance of compost selection for biodegradation studies.