Oxidation of anthracene by immobilized laccase from Trametes versicolor

The laccase of Trametes versicolor was immobilized on the functionalized nanoparticles SBA-15 with the average diameter less than 10 nm. Laccase mediated oxidations of anthracene (ANT) were investigated in the presence of two mediators, 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) and 1-hydroxybenzotriazole (HBT). Oxidation of ANT was more efficiently enhanced by adding 1 mM of HBT than that by adding ABTS. After 48 h oxidation HBT group significantly oxidized ANT with residue 58% relative to 88% in the ABTS group. HPLC and GC/MS analyses indicated the main product of ANT oxidation was anthraquinone (ANQ). The fluorescein diacetate (FDA) uptake of two human cell lines was used to assess the cytotoxicity and genotoxicity of ANT and ANQ. Treatments with ANT and ANQ at 5 and 10 μM exhibited significant cytotoxicity to the HaCaT cells and the A3 lymphocytes and no significant genotoxicity was observed. The results illustrated that ANQ is less toxic than ANT as well.