**4. Conclusions**

In this study, an atrazine-degrading bacterial strain with Cd resistance from herbicidepolluted soil was isolated. Based on 16S rRNA gene sequence analysis and physiochemical tests, the bacterium was identified as *Arthrobacter* sp., and designated as strain ST11. The ST11 cells were grown in MSM culture with atrazine as the sole source of carbon, nitrogen, and energy. The strain could degrade atrazine in crystal form or present in DEHP as NAPL. To the authors' knowledge, this study was the first to report an *Arthrobacter* strain actively degrading crystalline and NAPL-dissolved atrazine with Cd resistance. Cd2+ with concentrations < 0.5 and 0.5–1.5 mmol/L did not affect or slightly inhibited the growth of ST11 in LB, respectively. Correspondingly, in the whole concentration range (0.05–1.5 mmol/L), Cd2+ promoted ST11 to degrade atrazine, whether in crystalline form or dissolved in DEHP. Refusal to adsorb Cd2+ may be the main mechanism of high Cd resistance in ST11 cells. Therefore, ST11 may be a potential candidate for the industrial elimination of atrazine from contaminated arable soils with Cd pollution. However, insitu studies that examine the mechanisms of atrazine degradation and Cd resistance are necessary before this strain could be used in practice.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/catal12121653/s1, Table S1: Morphological, physiological, and biochemical properties of *Arthrobacter* sp. ST11; Figure S1: Photographs of colonies and cells of strain ST11: (A) photograph of ST11 colonies on LB solid media plate; (B) SEM photograph of ST11 cultured for 12 h; (C) SEM photograph of ST11 cultured for 36 h; Figure S2: The LC-UV chromatograms at 225 nm of atrazine standard (a), sample extract before atrazine degradation (b), and sample extract after atrazine degradation (c). The retention time of 5.081, 5.211, and 5.251 min is the absorption peak of atrazine. The retention time of 4.145 min was the absorption peak of a new metabolite.

**Author Contributions:** Conceptualization, J.Z.; Funding acquisition, T.P.; Investigation, J.Z.; Methodology, J.Z., Z.Y., Y.G. and M.W.; Resources, K.W.; Software, J.Z., Z.Y., Y.G. and M.W.; Supervision, T.P.; Validation, T.P.; Writing–original draft, J.Z.; Writing–review & editing, M.W., K.W. and T.P. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the National Natural Science Foundation of China (21866015); National Key Research and Development Program Project (2019YFC1805100); and the Program of Qingjiang Excellent Young Talents of JXUST (JXUSTQJYX2019011).

**Data Availability Statement:** The datasets are available from the corresponding author on reasonable request.

**Conflicts of Interest:** The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

## **References**

