Anaerobic digestion process for converting biodegradable films into volatile fatty acids

Overview

This solution addresses the growing challenge of recycling biodegradable packaging materials by converting them into volatile fatty acids (VFAs) through a controlled anaerobic digestion process. VFAs are valuable platform chemicals used in bioplastics, food preservation, pharmaceuticals, and bioenergy production. By selectively inhibiting methanogenic activity and optimizing operational parameters such as nutrient balance, pH, and temperature, the process accumulates VFAs as the primary end product rather than biogas. This approach creates a circular economy pathway for compostable packaging waste, transforming an environmental liability into a revenue-generating biochemical stream.

Technical specifications

Process approach:

• Sequential anaerobic digestion bioprocess with controlled hydrolysis and acidogenesis stages
• Inhibition of methanogen activity to redirect carbon flow toward VFA accumulation
• Optimization of operational parameters including nutrients, pH, and temperature

Validated capabilities:

• Testing of PLA-based bioplastics under thermophilic conditions in acidogenic anaerobic reactors
• Evaluation of materials with varying stereochemistry and crystallinity, showing that lower crystallinity PLA yields higher VFA concentrations at approximately 18 days reaction time
• Scalable infrastructure ranging from 1-liter laboratory semi-continuous digesters to a 300-liter pilot-scale reactor and a 2,000 cubic meter continuous stirred tank reactor (CSTR) digester

Future development targets:

• Development of a tailored microbial consortium for biodegradable film recycling
• Systematic analysis of hydrolysis rates and microbial community shifts under varying conditions
• Comprehensive feasibility assessment integrating material utilization efficiency, VFA yield, and energy input requirements

Technology readiness level

The technology is currently at laboratory validation stage (TRL 3-4). Initial proof-of-concept work has demonstrated VFA production from PLA materials under thermophilic acidogenic conditions, with material crystallinity identified as a key factor influencing yield. The research team possesses extensive anaerobic digestion infrastructure spanning lab to demonstration scale, enabling progression toward pilot validation. Planned work over the next twelve months includes batch culture hydrolysis studies, microbial community analysis, and integrated feasibility evaluation to advance toward larger-scale demonstration and eventual commercialization.