The persistence of heavy metals in soil and water due to anthropogenic activities is a key contributor to environmental contamination. In this study, the cadmium (Cd) resistant bacteria from a contaminated industrial sludge sample, screened through enrichment culture technique, and further characterized based on microscopy, biochemical tests, and 16S rRNA gene sequencing for species identification. Two Cd-resistant isolates, Pseudomonas sp. strain CS3 (accession number PP514684), and Pseudomonas sp. strain CS4 (accession number PP514689) were finally selected, identified, and further screened for their maximum tolerance concentration (MTC) for Cd, tolerating up to 250 and 200 mg/L of CdCl 2, respectively. Furthermore, the effects of various physical parameters (pH, contact time, and concentration) on Cd 2 + uptake by the bacterial cells were evaluated. Both strains CS3 and CS4 follow the pseudo-first-order kinetics, having a correlation coefficient (R 2 ) of 0.96326 and 0.96621, respectively, and also follow the Langmuir adsorption isotherm with R 2 of 0.97886 and 0.94808, respectively. Further, after 24 h, the initial Cd 2+ concentrations of 250 mg/L and 200 mg/L were reduced to 9.5 mg/L and 9.27 mg/L, respectively, which corresponds to 96.1% and 95.3% biosorption efficiency, reported for both strains. Hence, Cd 2+ adsorption property has been confirmed for the Pseudomonas strains CS3 and CS4. Therefore, this study provides outcomes for the good biosorption potential of the reported strains. Further, these strains can be explored for their potential for Cd bio-removal in bioremediation applications. • Isolation and screening of Cd 2+ resistant bacteria by enrichment culture technique. • The maximum tolerance concentration (MTC) of Cd- was determined. • New Pseudomonas knackmussii strain CS3 and Pseudomonas sp. strain CS4 were studied. • Biosorption efficiency of the Pseudomonas strains CS3 and CS4 determined. • The biosorption rate of 96.1 and 95.3% observed at optimum conditions.
Malik et al. (Sat,) studied this question.