Cagelike mesoporous silica encapsulated with microcapsules for immobilized laccase and 2, 4-DCP degradation
Junya Yang , Yan Huang , Yuxiang Yang
,
Hongming Yuan
,
Xiangnong Liu
DOI:10.1016/j.jes.2015.04.033
Received January 07, 2015,Revised April 09, 2015, Accepted April 17, 2015, Available online August 31, 2015
Volume 38,2015,Pages 52-62
In this study, cage-like mesoporous silica was used as the carrier to immobilize laccase by a physical approach, followed by encapsulating with chitosan/alginate microcapsule membranes to form microcapsules of immobilized laccase based on layer-by-layer technology. The relationship between laccase activity recovery/leakage rate and the coating thickness was simultaneously investigated. Because the microcapsule layers have a substantial network of pores, they act as semipermeable membranes, while the laccase immobilized inside the microcapsules acts as a processing plant for degradation of 2,4-dichlorophenol. The microcapsules of immobilized laccase were able to degrade 2,4-dichlorophenol within a wide range of 2,4-dichlorophenol concentration, temperature and pH, with mean degradation rate around 62%. Under the optimal conditions, the thermal stability and reusability of immobilized laccase were shown to be improved significantly, as the removal rate and degradation rate remained over 40.2% and 33.8% respectively after 6 cycles of operation. Using mass spectrometry (MS) and nuclear magnetic resonance (NMR), diisobutyl phthalate and dibutyl phthalate were identified as the products of 2,4-dichlorophenol degradation by the microcapsules of immobilized laccase and laccase immobilized by a physical approach, respectively, further demonstrating the degradation mechanism of 2,4-dichlorophenol by microcapsule-immobilized laccase.
