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GJ-22, a strain of the photosynthetic bacterium (PSB) capable of degrading cypermethrin (CPM), was isolated from the sludge from the wastewater treatment unit of an insecticide factory. The strain showed relatively high CPM degradation ability and was identified as Rhodopseudomonas palustris on the basis of its culture characteristics, co-lony and cell morphology, living cell absorption spectrum analysis, physiological and biochemical characteristics, type of internal photosynthetic membrane, and 16S rRNA sequence phylogenetic analysis. Single-factor tests showed that CPM degradation by GJ-22 was good from 25°C to 35°C, but that the optimal temperature was 30°C; a pH of 7.0 was optimal for both initial growth and CPM degradation. GJ-22 completely transformed CPM at a concentration of 50 mg/L at 30°C, pH 7.0, and 7,500 lux within 7 days. Under optimal conditions, within a week, GJ-22 degraded 83.5% of CPM, 77.1% of fenpropathrin, 71.2% of bifenthrin, and 31.1% of ethofenprox at concentrations of 100 mg/L. The metabolic products were detected by per-forming gas chromatography/mass spectrometry (GC/MS) analysis; the analysis showed that GJ-22 oxidation or/and hydrolysis degraded CPM, yielding 5 metabolites. [ABSTRACT FROM AUTHOR]

To isolate, select, identify and assess the potential for the biodegradation of fenpropathrin by photosynthetic bacterium, fenpropathrin-degrading photosynthetic bacteria were isolated by enrichment culture. Five isolates, which showed fenpropathrin biodegradation activity, were screened. Of these, strain PSB07-6 exhibited the highest fenpropathrin biodegradation potential, and was selected for further study. This strain was identified as Rhodopseudomonas sp. on the basis of morphology, physiological and biochemical characteristics, and 16S rRNA sequence analysis. The characteristics of this strain for degrading fenpropathrin were performed under different culture conditions. Optimum activity occurred at 35 °C and pH 7. Strain PSBO7-6 degraded 67.43% fenpropathrin (200 mg L-1) within 15 days. This strain could also degrade effectively cypermethrin, cyfluthrin, biphenthrin and esfenvalerate, except deltamethrin. Gas chromatography with mass selective detector (GC-MS) identified m-phenoxyphenyl-acetonitrile as the stable metabolic product, and from this a fenpropathrin biodegradation pathway is proposed. [ABSTRACT FROM AUTHOR]