benzofurans and 4-5-6-7-tetrachlorophthalide

Biodegradable plastics (BPs) were evaluated for their applicability as sustainable and solid H(2) donors for microbial reductive dechlorination of 4,5,6,7-tetrachlorophthalide (fthalide). After a screening test of several BPs, the starch-based plastic (SP) that produced the highest levels of H(2) was selected for its use as the sole H(2) donor in this reaction. Fthalide dechlorination was successfully accomplished by combining an H(2)-producing SP culture and a KFL culture containing Dehalobacter species, supplemented with 0.13% and 0.5% SP, respectively. The efficiency of H(2) use in dechlorination was evaluated in a combined culture containing the KFL culture and strain Clostridium sp. Ma13, a new isolate that produces H(2) from SP. Results obtained with this culture indicated increased H(2)-fraction for fthalide dechlorination much more in this culture than in compared with a KFL culture supplemented with 20mM lactate, which are 0.75 H(2)·glucose(-1) and 0.015 H(2)·lactate(-1) in mol ratio, respectively.

Topics: Bacteria, Anaerobic; Benzofurans; Clostridium; Hydrogen; Oxidation-Reduction; Plastics

The purpose of this study was the enrichment and phylogenetic identification of bacteria that dechlorinate 4,5,6,7-tetrachlorophthalide (commercially designated "fthalide"), an effective fungicide for rice blast disease. Sequential transfer culture of a paddy soil with lactate and fthalide produced a soil-free enrichment culture (designated the "KFL culture") that dechlorinated fthalide by using hydrogen, which is produced from lactate. Phylogenetic analysis based on 16S rRNA genes revealed the dominance of two novel phylotypes of the genus Dehalobacter (FTH1 and FTH2) in the KFL culture. FTH1 and FTH2 disappeared during culture transfer in medium without fthalide and increased in abundance with the dechlorination of fthalide, indicating their growth dependence on the dechlorination of fthalide. Dehalobacter restrictus TEA is their closest relative, with 97.5% and 97.3% 16S rRNA gene similarities to FTH1 and FTH2, respectively.

Topics: Benzofurans; Biotransformation; DNA, Bacterial; DNA, Ribosomal; Genes, rRNA; Hydrogen; Molecular Sequence Data; Peptococcaceae; Phylogeny; RNA, Bacterial; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Sequence Homology, Nucleic Acid; Soil Microbiology

Variation in the fungicide, 4,5,6,7-tetrachlorophthalide (phthalide), in paddy field soil was investigated in order to evaluate its decrease after aerial application by a radio-controlled helicopter. The maximum concentrations of phthalide were 309-320 microg/kg dry, which were 83%-96% of the applied phthalide. The organic carbon normalized soil sorption coefficient (K(oc)) was calculated to be 94-96 mL/g at 1 h after the application. The calculated K(oc) values increased to 620-1,300 mL/g from 1 through 9 days after the application and then 4,700-7,200 mL/g 14 days after the application. The half-life of the phthalide was calculated to be 20-31 days.

Topics: Adsorption; Agriculture; Benzofurans; Calibration; Gas Chromatography-Mass Spectrometry; Half-Life; Insect Control; Kinetics; Oryza; Pesticide Residues; Soil; Soil Pollutants; Water

Variation in the fungicide, 4,5,6,7-phthalide, in water was investigated in order to evaluate the runoff of the fungicide after aerial application to paddy fields by a radio-controlled helicopter. The survey was conducted for 4 months after the application. The average and maximum concentrations of phthalide were 3.7-4.4 microg/L and 30.5-33.8 microg/L in the paddy fields, 0.37-0.64 microg/L and 2.7-7.5 microg/L in the drainage channels, and 0.18 and 0.83 microg/L in a river, respectively. The runoff ratios of the aerially applied phthalide from the paddy fields into the drainage channels were calculated to be 1.7-2.4%.

Topics: Agriculture; Benzofurans; Environmental Pollution; Fresh Water; Fungicides, Industrial; Oryza; Pesticide Residues; Waste Management; Water Pollutants, Chemical