In this manuscript, the authors reported a metal resistant Paramecium species and its uptake ability of various metal ions like cadmium, copper, zinc, and lead. They believed that the microorganism they identified has a potential to absorb and degrade heavy metals for environmental treatment.
In general, this is an interesting study and may be suitable for publication in MRX. The following comments must be addressed before acceptance:
(1) Zinc, copper ions typically are not considered as the toxic metal ions, because they are also important nutrients. Please revise this.
(2) The genome information about the bacterial strain should be reported.
(3) The metal ion remediation mechanism should be discussed.
(4) The authors are suggested to compared their method using collected microorganisms for waste water treatment with other methods using synthetic polymer and inorganic materials. A few related papers are suggested to cite. https://doi.org/10.1088/2053-1591/abf520; https://doi.org/10.1088/2053-1591/aae03b; https://doi.org/10.1088/2053-1591/aae55c; https://doi.org/10.1088/2053-1591/ab56ea; https://doi.org/10.1088/2053-1591/ab43af; https://doi.org/10.1088/2053-1591/abd4b2; https://doi.org/10.1088/2053-1591/ab5f32; https://doi.org/10.1088/2053-1591/ac93ea;

My comments have been addressed in the revised manuscript. I can recommend the acceptance of this manuscript in its current form.