Wastewater a Potential Feedstock for PHA Biopolymers

A research team of 14 project partners from seven European countries has demonstrated a new method of wastewater treatment that simultaneously recovers compounds of interest while converting the remaining organic matter into a high-volume added value bio-based polymer

The Afterlife project demonstrated at the pilot level that wastewater streams from the confectionery industry, cheese manufacturing and citric fruit processing (both fruit juice and essential oils) could be converted into products of value such as essential oils, phenolic extracts, and raw materials for polyhydroxyalkanoate (PHA) biopolymers. A technology readiness level (TRL) of five was achieved, meaning the technology has been validated in a relevant environment. Level six of technology readiness is defined as “technology demonstrated in a relevant environment, and this represents the final stage of development before technology enters the deployment phase.

The treatment capacity of the operated pilots was one cubic meter of wastewater per day. The different pilot lines were operated sequentially and stopped at the end of August 2021. Essential oils and phenolic extracts production were comparable at lab and pilot scale. The pilot provided oils and extracts that could be tested in food products.

The filtration step for all wastewaters showed good results. For PHA production, different alternatives were tested. These included the use of different types of bacterial cultures (pure and mixed cultures) and operation times. The results indicate the necessity of a precise control system in order to achieve stable PHA production.

PHA-based materials were produced by project participant Lurederra (Spain). In order to improve the mechanical properties, PHA was combined with another bio-based polymer. Celabor (Belgium) successfully used the PHA material for the production of plastic trays for food packaging.

Essential oils and phenolic extracts can be used in food products such as smoothies, mayonnaise, green olives, fresh meat, lettuce gazpacho, and olive tapenade.

A PHA-based plastic tray for food packaging. Image: Celabor