Which bio-based products are obtained from urban bio-waste in RES URBIS?
The project is mostly focusing on converting urban bio-waste into:
- polyhydroxyalkanoate (PHA) and related PHA-based bioplastics
- bio-based solvents (to be possibly used also in PHA extraction)
- fibers (to be used for PHA-based biocomposites).
The authors of the present proposal are aware that several other bio-based products can potentially be obtained from the same bio-waste feedstock; however, after careful consideration, it was agreed that PHA has the best potential to be the main and a self-consisting pillar of the bio-waste biorefinery, especially because:
- its production process has the best potential to cope with large heterogeneity of the waste feedstock, in particular because the first production step, i.e. the acidogenic fermentation, is both robust and flexible and provides stable feedstock to the PHA production;
- PHA includes a whole family of copolymers with a wide range of tunable properties, so that PHA can be the main constituent of several bioplastics and their biocomposites, with a wide portfolio of applications.
- PHA is bio-based not only because it is produced from organic biomass, but also because it is produced through a process which is mostly biological under mild conditions (e.g. no sterile conditions are required). Thus, the PHA-producing bio-waste biorefinery can be fully sustainable from an environmental point of view, including an easier integration with existing biological plants for waste and wastewater treatment.
- In comparison with other biological processes, the PHA-producing process does not produce excess of sludge that needs to be handled, as the polymer makes up to 70% of the biomass.