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This study examined the interrelation between the biodegradation of polychlorinated biphenyls (PCBs) byCeriporiasp. ZLY-2010 and its fungal enzyme systems. The degradation rates of Aroclor 1254 and 1260 were 29.01% on day 5 and 36.80% on day 10, respectively. MnP (Manganese dependent peroxidase) and laccase activities showed the greatest increases in the samples containing Aroclors, indicating that extracellular enzymes ofCeriporiasp. ZLY-2010 were affected by the addition of Aroclors. However, the relationship between the biodegradation rate and extracellular enzymes might be obscured by the complexity of the biodegradation process. Cytochrome P450 monooxygenase was inhibited and the biodegradation rate of the Aroclor decreased by adding the inhibitor 1-aminobenzotriazole. Two-dimensional gel electrophoresis showed that intracellular enzymes play a significant role in the biodegradation of Aroclor. Complex extracellular and intracellular enzyme systems inCeriporiasp. ZLY-2010 play an important role in degrading PCBs. Physiological changes ofCeriporiasp. ZLY-2010 caused by PCBs appeared to affect biodegradation of PCBs. However, it is necessary to further study the unidentified enzymes related to the biodegradation of Aroclor. [ABSTRACT FROM PUBLISHER]

Polychlorinated biphenyls (PCBs) are difficult to degrade due to poor solubility, toxicity, and thermal stability. In the present study, the feasibility of PCB congener biodegradation by Ceriporia sp. ZLY-2010 was evaluated. The biodegradation rates of four PCB congeners, 4,4′-dichlorobiphenyl, 2,3′,4′,5-tetrachlorobiphenyl, 2,2′,4,5,5′-pentachlorobiphenyl, and 2,2′,4,4′,5,5′-hexachlorobiphenyl were evaluated. The degradation rate of 4,4′-dichlorobiphenyl was 34.03% on incubation day 13, while that of 2,2′,4,4′,5,5′-hexachlorobiphenyl reached 40.05% on incubation day 17. Therefore, Ceriporia sp. ZLY-2010 was degrading the higher PCB congeners more efficiently. PCB congener degradation products were extracted using acetone and ethyl acetate. No 2,2′,4,5,5′-pentachlorobiphenyl metabolites were detected in Ceriporia sp. ZLY-2010 culture, whereas 2,2′,4,4′,5,5′-hexachlorobiphenyl appeared to degrade to benzoic acid. However, intermediates of 2,2′,4,4′,5,5′-hexachlorobiphenyl were not detected during degradation. Therefore, additional studies should be performed to explore the mechanisms of PCB degradation. Our results indicate that Ceriporia sp. ZLY-2010 is able to degrade highly chlorinated biphenyls and has potential for use in PCB biodegradation and bioremediation. [ABSTRACT FROM AUTHOR]

The white rot fungus Stereum hirsutum was used to degrade methoxychlor [2,2,2-trichloro-1,1-bis(4-methoxyphenyl)ethane] in culture and the degraded products were extensively determined. The estrogenic activity of the degraded products of methoxychlor was examined using cell proliferation and pS2 gene expression assays in MCF-7 cells. S. hirsutum showed high resistance to methoxychlor 100 ppm, and the mycelial growth was fully completed within 8 days of incubation at 30°C. Methoxychlor in liquid culture medium was gradually converted into 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethane, 2,2-dichloro-1,1-bis(4-methoxyphenyl)ethylene, 2-chloro-1,1-bis(4-methoxyphenyl) ethane, 2-chloro-1,1-bis(4-methoxyphenyl) ethylene, and 1,1-bis(4-methoxyphenyl)ethylene, indicating that methoxychlor is dominantly degraded by dechlorination and dehydrogenation. MCF-7 cells were demonstrated to proliferate actively at the 10 -5 M concentration of methoxychlor. However, cell proliferation was significantly inhibited by the incubation with methoxychlor culture media containing S. hirsutum . In addition, the expression level of pS2 mRNA was increased at the concentration (10 -5 M) of methoxychlor. The reductive effect of S. hirsutum for methoxychlor was clear but not significant as in the proliferation assay. [ABSTRACT FROM AUTHOR]

The biodegradation and estrogenic activity of dibutylphthalate (DBP) were characterized in the white rot fungi, Phanerochaete chrysosporium, Trametes versicolor and Daldinia concentrica. The DBP resistance of these fungi was determined in a 2% malt extract agar medium. The biodegradation efficiency was tested in the concentration of 100 μM DBP, its degraded products were analyzed by HPLC and GC/MS, and the induction effect by DBP was measured by laccase and manganese peroxidase. The reduction of estrogenic effect was assayed by MCF-7 cell proliferation test and measurement of pS2 mRNA expression. Although the mycelium growth rate of D. concentrica was slow in the media containing DBP, its resistance to DBP was at the high concentration of 500 ppm. However, at the low concentration less than 100 ppm of DBP, the mycelium growth rates of P. chrysosporium and T. versicolor were superior to D. concentrica. The induction of laccase was effective in T. versicolor, but not in D. concentrica and P. chyrysosporium. The degradation efficiency was 94% in D. concentrica, 83% in T. versicolor after first day of incubation, and completely degraded after 6 days of incubation. However, proliferation of the cell lines was significantly blocked when the cells were incubated in the DBP culture medium of D. concentrica after 6 days of incubation. The levels of pS2 mRNA expression were decreased in supernatant from DBP treated with D. concentrica compared with DBP only treatment after one day of incubation. [Copyright &y& Elsevier]

Abstract: This study employed thermogravimetric analysis (TGA) and analytical Py-GC/MS in order to examine the catalytic effect of main inorganic metals (K, Mg and Ca) on the thermal degradation and the formation of pyrolytic products in lignocellulosic biomass. In addition, potential mechanisms of the primary pyrolysis in presence of the inorganic metals were derived. TG analysis showed that when potassium content increased in the biomass, char formation increased from 10.5wt.% to 19.6wt.% at 550°C, and temperatures at which the maximum degradation rate was achieved shifted from 367°C to 333°C. With increasing magnesium content, the maximum degradation rate increased from 1.21wt.%/°C to 1.43wt.%/°C. Analytical Py-GC/MS revealed that potassium had a distinguished catalytic effect promoting the formation of low molecular weight compounds and suppressing the formation of levoglucosan. An increase in the yield of C6 and C2C6 lignin derivatives with increasing potassium content was also observed. [Copyright &y& Elsevier]

Abstract: Poplar wood powders were treated with distilled water, tap water, HCl and HF, respectively, to remove inorganics from the biomass and to investigate effect of demineralization processes on pyrolysis behavior of the biomass. TG and DTG revealed that maximum degradation temperatures rose slightly from 362°C for control to 372°C, 366°C and 368°C after demineralization with distilled water, HCl and HF, respectively. Maximum degradation rates also increased from 0.96%/°C for control to 1.15%/°C for HF-biomass, 1.23%/°C for DI-H2O-biomass, and 1.55%/°C for HCl-biomass. Analytical pyrolysis-GC/MS of demineralized biomasses produced approximately 45 pyrolysis compounds. Total amount of low molecular weight compounds, such as acetic acid, acetol, and 3-hydroxypropanal, was significantly lowered in the demineralized biomasses. But levoglucosan increased 2–10-folds in the demineralized biomasses. One of the features regarding lignin derivatives was the reduction of the amount of C6-type phenols, such as phenol, guaiacol, and syringol after demineralization. [ABSTRACT FROM AUTHOR]