Flocculant recovery by mild fractionation techniques based on ionic liquids and aqueous two-phase systems


Summary: Extracellular Polymeric Substances (EPS) can be produced and excreted by mixed microbial cultures, e.g. by conversion of organic matter in industrial wastewater, which in another project at Wetsus already happens with 40-50% yields. A key process step, which is currently still undeveloped, is the recovery of EPS and fractionate them from other biomolecules such as proteins. We here propose to study recovery and fractionation of EPS by extraction with ionic liquids (ILs) as solvent, because ILs have been reported as effective and green solvents for biomass processing and in particular for cellulose dissolution. In order to keep the EPS intact, it is essential to apply mild techniques such as aqueous two-phase systems (ATPS) for the regeneration and reuse of the IL. We aim at stimuli responsive (redox-responsive or photoresponsive) polymers to form ATPS, and recover the EPS from the IL. By applying the stimulus after isolation of this phase, product fractions may be isolated from the added polymer by phase splitting, which then can be reused. The key research challenges in this project are 1) finding appropriate ILs for extraction of EPS from the broth, 2) developing stimuli responsive ATPS based on these ILs and commercial thermoresponsive and CO2-responsive polymers as well as in-house developed photoresponsive polymers, 3) study on the isolation of EPS fractions of different molar weights from the polymer rich phase by applying a stimulus (temperature, light, CO2), and study the behaviour of each fraction in flocculation processes, one of the possible applications of these EPS.





Dr. ir. B. Schuur

Verbonden aan

Universiteit Twente, Faculty of Science and Technology (TNW), Chemical Engineering


E.C Evangalista da Silva Antunes MSc


01/01/2019 tot 31/12/2023