Involvement of Fenton reaction in DDT degradation by brown-rot fungi

详细信息    查看全文

• 作者：Adi Setyo Purnomo ; Toshio Mori ; Ryuichiro Kondo
• 关键词：Biodegradation ; DDT ; Fenton reaction ; Brown-rot fungi ; Fomitopsis pinicola ; Daedalea dickinsii
• 刊名：International Biodeterioration and Biodegradation
• 出版年：2010
• 出版时间：October 2010
• 年：2010
• 卷：64
• 期：7
• 页码：560-565
• 全文大小：274 K

文摘

In this study, the ability of the brown-rot fungi (BRF) Fomitopsis pinicola and Daedalea dickinsii to degrade DDT (1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane) was investigated. F. pinicola and D. dickinsii degraded approximately 63 % and 47 % of total DDT in potato dextrose broth (PDB) medium, respectively. Degradation of DDT by D. dickinsii resulted in several metabolic products; DDD (1,1-dichloro-2,2-bis (4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis (4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis (4-chlorophenyl) ethylene), whereas degradation by F. pinicola produced only one metabolic product, DDD. Investigation was done to find out whether the Fenton reaction was involved in the degradation process. More DDT was degraded in medium lacking FeSO₄ than in that containing FeSO₄, suggesting that these fungi lack the benzoquinone-driven Fenton reaction cycle system. In addition, F. pinicola and D. dickinsii produced only very low levels of hydroxyl radicals (1.2 and 5.1 μM, respectively), which provides further evidence that these fungi lack the Fenton reaction cycle system. The addition of mannitol as a hydroxyl radical scavenger did not inhibit DDT degradation. Hydroxyl radical production increased when the medium was supplemented with Fe²⁺. Higher levels of hydroxyl radicals enhanced DDT degradation by D. dickinsii, but not by F. pinicola. These results indicate that F. pinicola and D. dickinsii have different mechanisms for degrading DDT from that reported for the BRF Gloeophyllum trabeum, in which the Fenton reaction is an important factor in DDT degradation.