A novel strain capable of degrading triclosan was isolated from the acclimated activated sludge and identified to be Dyella sp. WW1 based on 16S rDNA analysis. The effect of initial concentration of triclosan (0.2, 1, 5, and 10 mg/L), temperature (15, 25, and 35 °C), pH (5, 7, and 9), and additional carbon source on the degradation of triclosan was investigated in a mineral medium. The results showed that Dyella sp. WW1 can use triclosan as sole carbon source and degrade it when initial triclosan concentration was in the range of 0.2–10 mg/L. The optimal condition for Dyella sp. WW1 to degrade triclosan was 15 °C and pH 7. TOC removal efficiency was more than 90%. Dyella sp. WW1 can degrade 3,5-dichloro-4-hydrobenzoic via co-metabolism in the presence of triclosan, but cannot degrade trimethoprim, sulfamethoxazole, carbamazepine, and diclofenac. In the presence of glucose, Dyella sp. WW1 firstly utilized glucose to synthesize the biomass and then degraded triclosan. When triclosan concentration decreased to an extent (1.2 mg/L in this study), Dyella sp. WW1 started to use glucose again. The wastewater components did not significantly affect the activity of Dyella sp. WW1 to degrade triclosan. During the biodegradation process, six metabolite products were identified. Based on the metabolites, two degradation pathways were tentatively proposed. In summary, Dyella sp. WW1 could be used for degrading triclosan in the real wastewater.
Indole and phenol often coexist in the coking wastewater, while the effects of phenol on microbial communities of indole metabolism were less explored. In this study, the microbial interactions within activated sludge microbial communities stimulated by indole (group A) or by indole and phenol (group B) were systematically investigated in sequencing batch reactors (SBRs). The results showed that the removal of indole was increased by adding phenol. By using high-throughput sequencing technology, it was found that α-diversity was reduced in both groups. According to the relative abundance analysis, the indole-degrading genus Comamonas was the core genus in both groups (33.94% and 61.40%). But another indole-degrading genus Pseudomonas was only enriched in group A with 12.22% relative abundance. Meanwhile, common aromatic degrading genus Dyella and Thermomonas were enriched only in group B. It was found that the relative abundance of cytochrome P450 and styrene degradation enzymes were increased in group B by PICRUSt analysis. Based on the phylogenetic molecular ecological networks (pMENs), module hub OTU_1149 ( Burkholderia ) was only detected in group B, and the positive interactions between the key functional genus Burkholderia and other bacteria were increased. This study provides new insights into our understanding of indole metabolism communities stimulated by phenol, which would provide useful information for practical coking wastewater treatment.
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