Multimetal resistance and bioremediation potential of bacterial isolates from electroplating wastewate

Metal pollution in aquatic bodies is mostly caused by industrial operations such as electroplating industries. As a result, removing harmful heavy metals from water bodies is critical to preventing and reducing pollution from being transmitted deeper into the environment. Biological removal of these toxic heavy metals using metal-resistant bacteria is a more beneficial and inexpensive alternative that is worth pursuing. Bacteria possess catabolic capabilities and biodiversity, aiding in pollution removal and extracting an integrated system that relies on resistant bacteria to eliminate pollution. This study aimed to determine the ability of nine bacterial isolates previously isolated from electroplating effluent to grow, tolerate, and absorb copper, zinc, nickel, and chromium as individual metals and as a quaternary metal solution at 10–50 mg/L concentrations. As well, the most tolerant isolates were selected for estimating biosorption, bioaccumulation, and physiological activities under metallic stress intervals, such as pigment production, denitrification, and enzymatic activities. This study examines the removal of heavy metals from multicomponent adsorption systems using multimetal-resistant bacteria. It focuses on toxic heavy metal adsorption in multicomponent systems, discussing experimental operating factors, interaction mechanisms using equilibrium adsorption isotherms, kinetic mechanisms, and thermodynamic parameters, Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) for further evaluation of biosorbents. Nine isolates, individually and in consortium, belong to; Microbacterium paraoxydans, Streptomyces werraensis, Microbacterium arabinogalactanolyticum, Staphylococcus haemolyticus, Bacillus paramycoides, Bacillus megaterium, Sphingobacterium ginsenosidimutans, Kocuria rhizophila, and Sphingobacterium detergens, showed ability and significant differences in metal resistance, growth, and uptake, but the consortium was the most efficient. It was also found that the maximum time and rate of biosorption and bioaccumulation differ according to metal type and contact time (P≤0.05). Despite the physiological activities were reduced with an increase in cell old and high metal concentrations (P≤0.05), bacterial metabolism and viability continued under metallic stress. The spectral data confirm the presence of functional groups in the bacterial isolates responsible for the biosorption process. The overall adsorption process was best described by the Langmuir model, which fitted the equilibrium data of metals better than others. The pseudo-second-order kinetic model was also found to be in good agreement with the experimental results. The biosorption process was spontaneous and endothermic, as confirmed by thermodynamic parameters. The isolated bacteria have proven to be effective biosorbents with high tolerance and continuous physiological activities, even under stressful conditions.

Text 121204.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18552

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