Multi Metal Resistant Klebsiella pneumoniae KW is an Effcient Copper Accumulator and Bioremediator of Industrial Waste Water Maimoona Imran 1,2 , Soumble Zulfqar 2 , Hafsa Saeed 2 and Farah Rauf Shakoori 1 * 1 Department of Zoology, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan 2 School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan Article Information Received: 30 July 2020 Revised: 11 December 2020 Accepted: 22 February 2021 Available online 15 September 2021 Authors’ Contribution MI, SZ and HS performed the research work. MI and SZ wrote the article. FRS supervised the whole work. Key words Klebsiella pneumoniae, Copper uptake and effux, Bioremediation, Metal resistant bacteria Increasing concentrations of different essential and non-essential metals in the environment have posed a serious threat to all kinds of life. Bioremediation is considered as the best possible solution among the existing ones to reduce this kind of pollution. In the current study, copper resistant Klebsiella pneumoniae strains KW and CC were investigated for their bioremediation potential. Maximum uptake of Cu ++ by mid log phase cultures of KW and CC was 19.26 and 28.77µg per mg cell dry weight, respectively. The strains also exhibited effux ability; KW possessed more effcient effux system as it expelled 94.46% of maximum stored copper within 24 h as compared to 56% by CC. These strains were also found substantially resistant to some other toxic heavy metals generally present in the industrial effuents. These strains exhibited good growth in the wide range of pH (5-10) and temperature (25 -44°C). KW and CC were also investigated for their resistance potential against various antibiotics. KW was found to be resistant to broader range of antibiotics as compared to CC. All these characteristics viz., high tolerance against Cu ++ , excellent Cu ++ uptake and effux abilities, remarkable multi metal resistance potential and tolerance against substantial ranges of temperature and pH make K. pneumoniae KW an effcient tool for cleaning Cu ++ rich industrial effuents. INTRODUCTION E nvironmental pollution is a serious threat for mankind. Debris from mining and milling, liquid waste containing pesticides, radioactive waste containing fssion fragments and mainly effuents from various engineering and chemical industries are major contributors of anthropogenic emissions of heavy metals to the environment (Singh et al., 2017). Metals like as, Pb, Mn, Fe, Cd, Hg, Cu, Fe, Zn and Cr are used for number of medical and industrial applications. Copper has been used as an antifungal and antimicrobial agent in agriculture. It has also been used in hospitals to reduce the infections caused by bacteria (Hobman and Crossman, 2015). Whereas Zn ++ and Cd ++ are extensively used in batteries, electroplating, paints, pigments, topical creams, rechargeable cells and stabilizers (Hynninen, 2010; Orell et al., 2010; Outten and Munson, 2013). Although heavy metals are an essential constituent of all organisms as they are required for various biological * Corresponding author: farah.zool@pu.edu.pk 0030-9923/2021/0006-2175 $ 9.00/0 Copyright 2021 Zoological Society of Pakistan functions but when exceed in concentration, they become a threat for all forms of life including humans, animals, plants and microorganisms (Nies, 2003). Even the ppm level contamination of these metal ions can cause long-standing and incurable diseases (Tadesse et al., 2018). Excess of these metals damage cellular processes through generation of reactive oxygen species, reduction of various molecules, replacements of co-factors etc. All these lead to alteration in nucleic acids, proteins, oxidative phosphorylation and osmotic imbalance. They also interfere with the structures and functions of various enzymes by binding to thiol groups, and can even replace the prosthetic groups of those enzymes. They not only disturb the cellular functioning of cells but also accumulate in the cells and may ultimately lead to death of organism. One way to avoid the toxic effects of such metals is to reduce their amount in the environment. Therefore, industrial effuents, that contain large amounts of metal compounds, must be treated for effective removal of highly toxic metals and/or conversion into a non/less-toxic species. Removal of toxic heavy metal ions from waste water can be performed by various techniques. These methods include chemical precipitation (Fu and Wang, 2011), coagulation and focculation (López-Maldonado et ABSTRACT Pakistan J. Zool., vol. 53(6), pp 2175-2182, 2021 DOI: https://dx.doi.org/10.17582/journal.pjz/20200730092655