Q-205. Immobilized White Rot Fungi System Enhanced Dye Degradation under Non-Sterile Condition
Most reported studies using white rot fungus for the treatment or decolorization of dye have been performed under sterile conditions. The decolorization performance of dye could be deteriorated significantly due to contamination of bacteria and other microorganisms when sterilization conditions were not maintained or the white rot fungi were directly used under non-sterile conditions. To date, few studies have reported successful application of white rot fungi under non-sterile conditions. The bacterial contamination has been a challenge to use white fungi for the treatment of dye wastewater. It is unpractical to treat the wastewater containing dyestuff under sterile conditions. Therefore, it is of significance to develop strategies using white rot fungus under non-sterile conditions but with less negative impact of the contamination. We have developed a strategy using immobilized white rot fungi Phanerochaete chrysosporium onto inert carriers for biodegradation of reactive dye K-2BP under non-sterile condition. The negative impact caused by bacterial contamination was not observed. The optimal operational parameters were selected through series orthogonal experiments using the activity of manganese peroxidase (MnP) as an evaluation index. We compared four different inert carriers and found that the best carrier was polyurethane foam with a size of carrier of 1.0×1.0×1.0 cm3 with three-prismatoid in shap. The specific gravity of the carrier was 1.2 g/100L. Compared with suspended culture, in the treatment system using immobilized white rot fungi the growth of microzymes, coccies, and bacillus was effectively restrained under non-sterile condition, pH was maintained steadily, and the rate of carbon and nitrogen consumption was increased, resulting in acceleration of enzyme production and enhancement of peak level of the enzyme. In the immobilized fungi system, the enzymatic activity was observed at MnP 683U/L, which was as 5 times as high of that in a suspended culture system. The decolorization efficiency for reactive dye K-2BP under non-sterile condition was similar to that under sterile condition. The decolorization percentage was 69% after 24h and 93.5% after 3d, respecitively. After 3d, the decolorization in immobilized fungi system was 80% higher than that observed in suspended culture . This strategy reduced operational period by 3d. In conclusion, the immobilized white rot fungi system had significantly reduced the negative impact of bacterial growth on biodegradation performance of white rot fungi and effectively decolorize and degrade reactive dye K-2BP under non-sterile cultivate condition.