Hydrophobic mixed culture for 1,2-dichloroethane biodegradation: Batch-mode biodegradability and application performance in two-phase partitioning airlift bioreactors

Recent studies highlighted that hydrophobic microorganisms played key roles in VOC removal performance of two-phase partitioning bioreactors (TPPBs). The objective of this study was to evaluate the performance of a hydrophobic mixed culture for 1,2-dichloroethane (1,2-DCA) biodegradation in both batch and TPPB tests. The hydrophobic mixed culture with cell surface hydrophobicity of 79% was acclimated from an activated sludge able to efficiently degrade 1,2-DCA as sole carbon and energy source. It was primarily composed of Xanthobacter genus (62%). Nearly complete degradation with coefficients of 0.80 mg(co2) mg(1,2-DCA)(-1) and 0.66 mg(cl)(-) mg(1,2-DCA)(-1) was achieved for a wide range of 1,2-DCA concentrations (114.1-1141.5 mg L-1) in the presence of silicone oil. The maximum specific growth rate was 0.247 h(-1) which was approximately two times the values of previous pure strains. The two-phase partitioning airlift bioreactors inoculated with the hydrophobic mixed culture was robust against step changes of gas flow rates and spike changes of inlet 1,2-DCA concentrations. All data proved the potential of the hydrophobic mixed culture for toxic-VOC removal in the TPPBs. (C) 2018 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.