Background

To date, the polymers that can be involved in the realization of sustainable packaging range from recycled polymers to compostable biodegradable polymers, as well as bio-based but non-biodegradable polymers. The production of biobased polymers using waste as second generation raw material is finding large application. Nonetheless, specialization of biorefineries that can convert waste into new biobased products is still to come.

The proposed invention is a process of anaerobic digestion in separate phases to optimize the biological production of Polyhydroxyalkanoates (PHAs ‑ precursor to bioplastics) from the organic fraction of domestic solid waste. This method uses mixed microbial cultures (MMCs) and is based on the combination of a three-stage biological process in sequence with a two-step fermented flow filtering system to reduce the concentration of suspended solid particles and nutrients. The produced PHAs can be used as interlayer in packaging film (also with the addition of nanoparticles for properties improvement) and other bioplastic applications. ()

Technology Overview

The method is adapted to reuse domestic or other organic waste, with a residual solids content greater than 10.0 g/L, as raw material in the production of bioplastics and biogas. () The method is based on the combination of a biological process in three sequential phases (Phase I: anaerobic fermentation, Phase II: sequential aerobic fermentation, Phase III: batch aerobic fermentation), with a flow filtering system. After a first filtration of the discharge from Phase I, the flow is divided between the reactor for Phase II, where the biomass is produced and a membrane filter before entering Phase III, where the Polyhydroxyalkanoates (PHAs) are accumulated. This second filtration step reduces the concentrations of particulate matter and nutrients, favoring the synthesis of PHAs ().

Stage of Development

Technology Readiness Level (TRL) 5-6

Benefits

Reuse of organic waste with TSS > 10.0g/L
Flexible enough to cope with different waste management systems
Two different solids removal steps
First filtration favors specialized biomass production
Second filtration favors maximization of PHAs production
Easily integrated with existing anaerobic digestion plants
Offer economic gain while maintaining PHAs at an affordable price

Applications

PHA can be used as:

Interlayer film: pure component through electrospinning.
Adjacent adhesive market: bio substitutes of polyether polyurethanes.
Packaging film: up to 25% of PHA content in the formulation.
Durables: e.g. flexible handles, interior furniture: up to 60% in the formulation.
Environmental remediation: a niche application in which PHA has shown good performances.

Opportunity

Open to collaborative projects to further develop the technology and/or licensing.

Bioplastics from Organic Fraction of MSW

Patents

IP Status

Seeking