The examination of the performance of raw and immobilized S. (Saccharomyces) cerevisiae in the simultaneous abatement of metal ions from wastewater effluent is the focal point of this article. The optimal storage time for raw and immobilized S. cerevisiae, during which they can be utilized, was estimated. The outcomes revealed that as the initial metal ion concentrations increased, the adsorption capacity improved, while the removal efficiency of S. cerevisiae yeast cells decreased, with the highest uptake obtained at the optimal conditions: pH = 5.0, 2.0 g S. cerevisiae/L, 25 °C, and a contact time of 25 min. The maximum adsorption capacities (q_max) for Pb(II), Cd(II), and Ni(II) ions are shown by Langmuir at 65, 90, and 51 mg/g, respectively. It was discovered that the metal ions’ biosorption reactions were spontaneous and were fitted by the pseudo-second-order model. The mechanisms of the metal ions’ abatement were explained by using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), (BET) Brunauer–Emmett–Teller, and TEM (transmission electron microscopy) outputs. EDTA and citric acid can eliminate more than 70 ± 4 and 90 ± 5% of the adsorbed ions, respectively. The experiment of storage demonstrated that the immobilized S. cerevisiae was more stable for 8 months than the raw yeast.

This study developed a new technology for decontaminating pesticides and maximizing the efficiency of the biodegradation process through experimental design methodology. Pseudomonas putida OR084957 previously isolated from agricultural wastewater had showed promising biodegradation capability of P. putida of 79.0% and 83.1% for malathion and chlorpyrifos, respectively. In this study, the biodegradation capabilities of Pseudomonas putida OR084957 were further optimized using response surface methodology (RSM) derived from Box–Behnken experimental design. Pesticides biodegradation was found to be markedly influenced by pH, incubation time and bacteria dose with P -value lower than 0.05. The optimal conditions for maximum degradation were determined to be pH 7, a pesticide concentration of 100 mg L⁻¹, an incubation time of 9 days, and a bacterial volume of 3 v/v. Under these conditions, the degradation percentages of malathion and chlorpyrifos reached 93.81% and 98.01%, respectively. The potential of P. putida for biodegrading organochlorine compounds in real water samples was also evaluated, demonstrating its promise as an economical, efficient, and sustainable agent for pesticide removal from wastewater. This study demonstrated that unique strain is a highly effective microorganism to biodegrade malathion and chlorpyrifos, suggesting its potential use as a sustainable and cost - effective solution for remediating pesticide - contaminated water bodies. Graphical Abstract