Isolation and Characterization of an Aerobic Cyanuric Acid-Utilizing Bacterium

摘要

In a previous study, degradation of a triazine-herbicide, atrazine, by photocatalytic oxidation (PCO) leads to the production of a PCO-resistant compound - cyanuric acid (CA). In order to completely mineralize atrazine after PCO treatment, an aerobic CA-utilizing bacterium was used to further degrade CA produced. Among several CA-utilizing bacterial strains isolated from the soil samples collected from various agricultural sites in Hong Kong, Sphingomonas capsulata, which had the highest CA-utilization ability, was selected for further characterization and optimization of CA-utilization. The optimal physico-chemical conditions including incubation temperature, initial pH of the culture medium, agitation rate, and initial concentrations of CA and glucose for the bacterium to utilize CA were determined. The possibility of using the two-stage (i.e. PCO and degradation by S. capsulata) treatment to completely degrade and detoxify atrazine will be discussed.