BACKGROUNDSolid-liquid two-phase partitioning bioreactors (TPPBs) use polymers as the sequestering phase to reduce the concentration of substrates to sub-inhibitory levels and enhance biodegradation performance. Polymer selection for TPPBs is challenging due to the almost infinite variety of target substrates to be degraded, and the variability and complexity of polymer composition and structure. RESULTSThree different polymer selection criteria, based on either solubility parameters or activity coefficients, were assessed via experimental partitioning coefficients (PCs) for phenol and butyl acetate, two substantially different target contaminant molecules, and the relative ability of the three methods to predict effective polymers was assessed. The best method was also applied to predict which waste polymers would be effective for sequestering these molecules, and TPPB degradation tests were conducted to confirm the effectiveness of a single identified polymer and selected waste polymers. CONCLUSIONAn effective polymer selection criterion was identified and the identified polymer showed a high capacity to absorb both phenol and butyl acetate. Both substrates were successfully degraded in solid-liquid TPPBs using the selected polymer and using mixtures of waste polymers. (c) 2013 Society of Chemical Industry