Characterisation of an efficient atrazine-degrading bacterium, sp. ZXY-2: an attempt to lay the foundation for potential bioaugmentation applications.

BACKGROUND

The isolation of atrazine-degrading microorganisms with specific characteristics is fundamental for bioaugmenting the treatment of wastewater containing atrazine. However, studies describing the specific features of such microorganisms are limited, and further investigation is needed to improve our understanding of bioaugmentation.

RESULTS AND CONCLUSIONS

In this study, strain sp. ZXY-2, which displayed a strong capacity to degrade atrazine, was isolated and shown to be a potential candidate for bioaugmentation. The factors associated with the biodegrading capacity of strain ZXY-2 were investigated, and how these factors likely govern the metabolic characteristics that control bioaugmentation functionality was determined. The growth pattern of sp. ZXY-2 followed the Haldane-Andrews model with an inhibition constant () of 52.76 mg L, indicating the possible augmentation of wastewater treatment with relatively high atrazine concentrations (> 50 ppm). Real-time quantitative PCR (RT-qPCR) results showed a positive correlation between the atrazine degradation rate and the expression levels of three functional genes (, , and ), which helped elucidate the role of strain ZXY-2 in bioaugmentation. In addition, multiple copies of the gene were putatively identified, explaining the higher expression levels of this gene than those of the other functional genes. Multiple copies of the gene may represent a compensatory mechanism that ensures the biodegradation of atrazine, a feature that should be exploited in future bioaugmentation applications.