Ricerc@Sapienza

This project aims at developing a multi-stage process for polyhydroxyalkanoates (PHA) production by mixed microbial cultures (MMC) whereby the combination of physical-chemical and biotechnological steps offers an innovative route to connect the upcycle of conventional plastic wastes through their conversion into new bio-based and biodegradable polymers, so fullfilling the principles of circular economy.
Although the use of MMC for PHA production from fermentable organic waste is being studied for several years at laboratory scale and recently also at pilot scale, plastic waste is still an unexplored feedstock. An initial physical-chemical pretreatment stage is required to make this waste a suitable substrate for its biological conversion and the obtained composition of the pretreated carbon source primarily affects the polymer composition, which also depends on the performance of the following biological stages.In particular, a pivotal role is played by the microbial selection stage since the better its operation the higher the PHA production in the accumulation reactor which, in turn, affects the following extraction step.
Indeed, downstream steps are also quite important, which include not only PHA extraction from biomass but also its further processing into bioplastics with desired properties. In particular, functionalisation to confere anti-microbial activity and 3D-printing will be investigated.
To achieve these targets , the project is organized into 3 Workpackages, each one containing significant steps forward with respect to the state of art:
WP1: Physical-chemical pretreatments of plastic wastes, including a combination a thermal treatment and chemical oxidation , either in sequence or simultaneously
WP2: Set-up of a biological system for PHA production with MMC, with a brand new approach of a sequence of continuous reactors
WP3: Downstream processing, including supercritical fluid PHA extraction, antimicrobial functionalization and 3-D printing