Isolation and characterization of a dimethoate-degrading bacteria strain LPx and its degradation characters

A dimethoate-degrading bacteria strain LPx was acclimated with dimethoate as sole source in self-made acclimatization device.The strain was identified as Pseudomonas sp.base on its physiological characteristics and 16S rRNA sequence(GenBank Accession No.HM488993)analysis.Batch dimethoate biodegradation experiments were conducted to determine the effect of pH,temperature,inoculation amount and initial dimethoate concentration on the degradation efficiency.Results showed that under the optimum operation conditions(pH was 7.5,temperature was 30 ℃ and inoculation rate was 10%),the bacteria caused complete degradation of dimethoate(100 mg/L) in 120 h.This biodegradation process of dimethoate could be well described by first-order kinetic model.The maximum substrate utilization rate,Miehaelis-Menten constant and inhibitory constant were 0.734 d-1,21.700 mg/L and 259.215 mg/L,respectively.