Biodegradation of physicochemically treated polycarbonate by fungi.

Two fungal strains isolated from soil and a commercial white-rot fungus, Phanerochaete chrysosporium NCIM 1170 (SF2), were tested for biodegradation of untreated, UV-, and thermal-treated bisphenol A polycarbonate (PC). The isolated strains based on 18S rDNA analysis were characterized as Engyodontium album MTP091 (SF1) and Pencillium spp. MTP093 (SF3). About 5.4% weight loss and 40% reduction in M(n) were observed for UV-treated polycarbonate in one year with SF2 strain. An increase in surface energy and oxygen content and a reduction in methyl index indicated oxidation of PC during this period. PC exposed to the SF1 strain showed a 15 degrees C decrease in glass transition temperature, indicating an increase in the number of chain ends and, hence, an increase in the free volume of polymer. No bisphenol A, the monomer of PC, was detected during the study. NMR and FTIR spectra showed the formation of methyl groups due to pretreatments. EDAX analysis exhibited surface oxidation of the PC. The current study advocates that biodegradation of PC can be enhanced by pretreatments.