Assessment of the efficiency of U-tube continuous bioreactor and immobilized enzyme beads for dye decolourization.

Two bioreactors (column and U-tube) were compared for continuous dye decolourization efficiency using a laccase-producing white rot fungus, Phlebia radiata. Column bioreactor containing immobilized crude enzyme beads and U-tube continuous bioreactor containing actively growing fungal biomass were established. Synthetic dye (coracryl blue C5G) solution treated with immobilized crude enzyme on alginate beads showed a maximum net decolourization up to 55% (flow rate 1 ml/min). The U-tube bioreactor was more efficient in decolorizing the dye, which showed a net decolourization up to 64% at faster flow rate (2.5 ml/min). The decolorization efficiency in both the systems was positively influenced by the slower flow rate. Thus, the study presents designing and operations of two continuous small-scale bioreactors one with immobilized enzyme while the another one with direct fungal contact.