ORIGINAL ARTICLE 16S rRNA molecular profiling of heavy metal tolerant bacterial communities isolated from soil contaminated by electronic waste Pankaj Kumar 1 & M. H. Fulekar 1,2 & R. Y. Hiranmai 1 & Ramesh Kumar 3 & Rajesh Kumar 4 Received: 19 February 2020 /Accepted: 29 June 2020 # Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i. 2020 Abstract Electronic waste is an evolving source of harmful pollutants in our surrounding environments and considered to be perilous as it contains toxic metals such as chromium, cadmium, lead, mercury, zinc, and nickel in huge quantities. Heavy metals are harmful contaminants and accumulated in the environment due to various anthropogenic activities. The present study was conducted to isolate and characterize different heavy metal tolerant bacterial species, based on molecular techniques from soil contaminated by electronic waste. The contaminated soil samples were analyzed for various physicochemical properties such as pH, electrical conductivity, soil moisture, water holding capacity, organic carbon, organic matter, available phosphorus, total nitrogen, and potassium using standard procedures. The soil samples were found to contain a higher amount of different heavy metals such as copper, chromium, lead, iron, cadmium, and nickel. Serial dilution and spread plate techniques have been used for bacterial isolation. The identification and molecular characterization of isolated bacterial species were done by biochemical tests and 16S rRNA gene sequencing technique. The 16S rRNA sequencing analysis confirmed the presence of different bacterial species as, Micrococcus aloeverae, Kocuria turfanensis, Bacillus licheniformis, Bacillus jeotgali, Bacillus velezensis, and Bacillus haikouensis. The findings indicated that the e-waste dumping sites are the storehouse of elite bacterial species. The present research study offers a platform for systematic analysis of e-waste sites by microbial profiling that may help in the innovation of novel microorganisms of scientific importance and better biotechnological potential. Keywords Electronic waste . Heavy metals . Microbial diversity . 16S rRNA gene sequencing . Phylogenetic tree analysis Introduction Electronic industries are releasing a huge amount of electronic waste (e-waste) in the environment at a rate of 20–50 million tons per year (Duan et al. 2009; Wang et al. 2013). According to the assessment of the United States Environmental Protection Agency (USEPA), only 15–20% of e-waste can be recycled, whereas the remaining parts are often disposed of in landfills (USEPA 2012). E-waste is supposed to be very diverse and composite that significantly involves disposed electrical and electronic parts (Kiddee et al. 2013; Heacock et al. 2016). E- waste usually comprises a high amount of toxic substances including organic pollutants (e.g., polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs)) and heavy metals (Pb, Zn, Cu, and Cd) (Kumar 2018). Therefore, if these e-wastes are disposed of improperly, these harmful substances pose a severe risk to the environment as well as human health. The constituents of e-waste are chemically and physically distinct from other municipal or industrial wastes which pose a different type of health risk. The chemical com- positions of e-waste depending on the age and type of the discarded items mostly composed of a mixture of heavy metals attached to, covered with, or mixed with various types of plas- tics and ceramics (Hoffmann 1992; Robinson 2009). Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12223-020-00808-2) contains supplementary material, which is available to authorized users. * Pankaj Kumar pankajb434@yahoo.com 1 School of Environment and Sustainable Development, Central University of Gujarat, Gandhinagar, Gujarat 382030, India 2 Center of Research for Development, Parul University, Vadodara, Gujarat 391760, India 3 Department of Environmental Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida 201310, Uttar Pradesh, India 4 Department of Environmental Science, School of Earth Sciences, Central University of Rajasthan, Ajmer 305817, Rajasthan, India https://doi.org/10.1007/s12223-020-00808-2 / Published online: 21 July 2020 Folia Microbiologica (2020) 65:995–1007