Deliverable 2.6 - 2nd report on PHA extraction
This report addresses the progress obtained in the development of a novel PHA purification process in the last year, starting from the technology status as reported on deliverable D2.3.
The main goal of this task is to develop a PHA purification process that does not use any fossil-based organic solvents and that can be implemented in typical wastewater treatment plants using mild conditions. In D2.3 a new method was presented that enabled obtaining a polymer with adequate properties and without the chlorine smell typical of the polymer purified using sodium hypochlorite, which is not suitable for further use of the polymer by processors. All development reported in D2.3 had been carried out on PHA-containing biomass obtained from food waste processing at NOVA ID, and was essential to adapt the benchmark processes. In the last year, focus was on optimizing the process to enable its use on PHA-biomass obtained by UNIRM at the Treviso pilot plant using a mix of squeezed organic fraction of municipal solid waste (OFMSW, 30-35%) and thickened waste activated sludge (WAS, 65-70%), reducing the amounts of reagents used, checking the specifications of the obtained polymer, validating its usefulness for the intended final applications and starting the process scale-up. In addition to the results regarding to the advances in the development of an aqueous PHA extraction method, this deliverable also presents the results obtained in the use of ethyl acetate and supercritical carbon dioxide as extractants, which could also provide environmentally friendly routes as compared to the use of fossil-based organic solvents.