一株丛毛单胞菌对2-吡啶甲酸的好氧生物降解

A strain which uses 2-picolinic acid as the sole source of carbon, nitrogen and energy was isolated under aerobic condition. Based on 16S rRNA sequence analysis, this strain was identified as Comamonas sp. and named as ZD3. The effects of pH and initial concentrations of 2-picolinic acid on the degrading capacity of ZD3 were investigated. It was found that ZD3 could degrade 2-picolinic acid effectively in a pH value range of 5.0-9.0, wherein 7.0 was proved to be the optimal pH value. When the initial concentration of 2-picolinic acid was 100, 200, 400, 600 and 800 mg•L^-1, ZD3 could completely degrade 2-picolinic acid within 12, 17, 20, 78 and 114 h, respectively. And zero-order kinetic model could better express the degradation behavior of 2-picolinic acid by ZD3 than first-order kinetic model. It was observed that in the concentration range of 100-400 mg•L^-1, the degradation rate constant (k₀) increased with the concentration and reached the maximum at 400 mg•L^-1. However, in the concentration range of 600-800 mg•L^-1, k₀ began to decrease, indicating an inhibitory effect. Moreover, ultraviolet spectrum and high performance liquid chromatography-ion trap-time of flight mass spectrometry showed that in the aerobic degradation of 2-picolinic acid, the first reaction was α hydroxylation so that 6-hydroxy picolinic acid was produced.