Breeding efficient aerobic denitrifier by UV-irradiation

An aerobic denitrifier R1 was mutagenized by UV-irradiation and an effective mutant was obtained, named ZR43. Results showed that the accumulation of NO₂^--N by ZR43 significantly decreased to 17.42mg/L and the removal rate of TN increased by 18% compared with parent strain R1. The mutant ZR43 was identified as Arthrobacter sp. by 16S rDNA sequences analysis. The cell of ZR43 was rod, G⁺, and the characteristics of colony were circular, yellow, low-convex, smooth and wetness with regular margins. The optimum condition for the growth of strain ZR43 was as follows: 30°C, pH = 8, C/N ratio = 10, and succinic acid as carbon source. Moreover, C/N ratio had a significant effect on aerobic denitrification performance of strain ZR43 and the removal rate of TN increased along with the increasing C/N.