Bioaugmentation potential of a newly isolated strain Sphingomonas sp. NJUST37 for the treatment of wastewater containing highly toxic and recalcitrant tricyclazole.

In order to develop an effective bioaugmentation strategy for the removal of highly toxic and recalcitrant tricyclazole from wastewater, a tricyclazole degrading strain was firstly successfully isolated and identified as Sphingomonas sp. NJUST37. In batch reactors, 100 mg L-1 tricyclazole could be completely removed within 102 h, which was accompanied by significant biomass increase, TOC and COD removal, as well as toxicity reduction. Chromatography analysis and density functional theory simulation indicated that monooxygenation occurred firstly, followed by triazole ring cleavage, decyanation reaction, hydration reaction, deamination, dihydroxylation and final mineralization reaction. Tricyclazole biodegradation condition by NJUST37 was optimized in terms of temperature, pH, tricyclazole concentration and additional carbon and nitrogen sources. After the inoculation of NJUST37 into a pilot-scale powdered activated carbon treatment tank treating real fungicide wastewater, tricyclazole removal efficiency increased to higher than 90%, demonstrating the great potential of NJUST37 for bioaugmentation particularly on tricyclazole biodegradation in practice.