Abstract
Coriolus hirsutus IFO 4917 has the ability to degrade various xenobiotics. This study was concerned with kinetics of soil-bioremediation with this fungus. Bisphenol A (BPA; 2,2-bis (4-hydroxyphenyl) propane), which is a hormone-disrupting chemical but used widely as a raw material for polycarbonates, epoxy resins, phenol resins and polyesters, was used as a model xenobiotics. The soil contaminated with BPA was treated by C. hirsutus at different conditions. The fungus was pre-cultured using MYG medium (malt extract: 10 g/L, yeastextract: 4.0 g/L and glucose: 4.0 g/L) for 3d on a shaker at 298K. Contaminated soil was prepared by adding a fixed amount of BPA-ethanol solution into a fixed amount of commercial soil that were sterilized by autoclave five times. Soil moisture content was adjusted with distilled water. The bioremediation was performed in a 300mL Erlenmeyer flask (reactor A) and a 40mL fixed-bed (reactor B). Reactor B was cylindrical type had a fused-in fritted glass disc (pore size: 100-160 µm) at the bottom. At the beginning of incubation, pre-cultured fungus was inoculated into the prepared soil in the reactor. During incubation, the moisture was kept constant by daily addition of distilled water. BPA in treated soils was extracted and analyzed using HPLC. In reactor A at 40%-moisture about 92% of initial BPA was degraded for 35d. Experimental parameters were changed and their effects on the degradation were studied. The increase in the soil moisture had a positive effect on the biodegradation. In the experiment with reactor B, the aeration stimulated the biodegradation.
