Metal-Tolerant Bacteria of Wastewater Treatment Plant in a Large City

Abstract

Biological treatment methods are the most important part of the treatment process for domestic wastewater, the amounts of which are increasing every year due to rapid, unregulated urbanization and the rising number of people living in such areas. At the same time, microorganisms existing in treatment facilities should not only effectively utilize organic pollutants, but also be resistant to a variety of organic and inorganic contaminants. This study’s objective is to isolate and identify—using molecular genetic techniques—strains of bacteria that tolerate concentrations of heavy metals (Ni, Cd, Pb, Zn and Cu) in the 3–5 mM range. They were sourced from water and sludge samples obtained from sewage treatment facilities in a large city. Outcomes of phylogenetic analysis of 16S rRNA gene sequences revealed that tolerant strains of bacteria belonged to the genera Pseudomonas, Serratia and Klebsiella; strains belonging to the genus Pseudomonas dominated. Of ten resistant strains, nine were isolated from sludge and water samples of the secondary sedimentation tank, and the other one from a treatment plant’s digester. Changes in the color of microorganisms’ colonies became evident when cultivated on media enriched with heavy metals. Cultivating nonpathogenic strains of these bacteria and their introduction into communities of other activated sludge microorganisms could have practical application to biological decontamination of wastewater.

Antibiotic Resistance in Metal-Tolerant Microorganisms from Treatment Facilities

“…Samples of wastewater and active sludge from the secondary sedimentation tank and methane tank (digester) and different ages of mixed sewage sludge samples from the large city wastewater treatment plant were taken to isolate metal-tolerant microorganisms [20]. The concentration of heavy metals and metalloids in the waters and sludge of the treatment plant was measured by optical emission spectrometry with inductively coupled plasma (Optima-5300DV, Perkin Elmer, Waltham, MA, USA).…”

“…The concentration of these elements in the collected samples of sewage sludge was measured by atomic absorption spectrometer with flame atomization of samples Analytik Jena contrAA ® 800 (Analytik, Jena, Germany). By cultivating on LB medium with salts Ni, Co, Cd, Zn, Pb, and Cu bacterial strains that were tolerant to these metals at concentrations of 3-5 mmol were selected and identified after Sanger sequencing [20]. Initial phylogenetic screening for the similarity of the 16S rRNA gene nucleotide sequences was carried out in the GenBank database (National Center for Biotechnology Information), using the BLAST software package.…”

“…The number of aerobic bacteria isolated from samples of water and activated sludge from treatment facilities was secondary settling tank active sludge-2.8 × 10 6 cells/mL, secondary settling tank water-2.4 × 10 5 cells/mL and digester-1.6 × 10 5 cells/mL. Antibiotic resistance testing was carried out for 10 metal-tolerant strains [20] to 6 different antibiotics. The test results are shown in Table 2.…”

Influence of aluminum nanoparticles in epoxy resin and epoxy coating for anticorrosion and antibacterial protection in pipeline industry

“…Empirical records compiled from a variety of sources suggest that globally more than 330 km 3 year −1 of municipal wastewater is produced 3 . Over half of the population living in clusters in the European Union produces on a daily basis wastewater that amounts to 41.5 million m 3 4 . An excessive amount of wastewater, affects the strength of the material, mechanical properties, physical appearance, as well as its operation and lead to degradation of infrastructure 5 .…”

Anticorrosion and Antibacterial Properties of Al NP–Epoxy Nanocomposite Coating on Grey Cast Iron

“…The microbiological community that exists in wastewater is usually a combination of various types of bacteria, among which are pathogenic forms such as opportunistic pathogens (Enterobacter cloacae, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus vulgaris or Pseudomonas aeruginosa), obligate pathogens from Salmonella and Shigella genera and enteropathogenic strains of Escherichia coli. It can also contain viruses, protozoa, fungi, flatworms, roundworms, and similar [13,14]. The rod-shaped Gram-negative aerobic bacteria P. aeruginosa prefer moist environments such as urban runoffs and sewage effluents [15].…”