Multimetal bioremediation from aqueous solution using dead biomass of Mucor sp. NRCC6 derived from detergent manufacturing effluent

Among ten metal-tolerant fungal isolates obtained from the microbiomes of detergent industry effluent, Mucor sp. NRCC6 showed the highest tolerance and an adaptive behavior toward the heavy metals Ni(2+), Pb(2+), Mn(2+), and Zn(2+). It gave the highest growth rates 0.790 ± 0.59, 0.832 ± 0.32, 0.774 ± 0.40, and 0.741 ± 1.06 mm/h along with the lowest growth inhibition 9.19, 4.37, 11.04, and 14.83% in the presence of Pb(2+), Zn(2+), Ni(2+), and Mn(2+), respectively, at a concentration of 5.0 g/L. Then, Mucor sp. NRCC6 was selected as a biotrap for the removal of these heavy metals. The optimized operating conditions were detected to be pH 6.0 for Pb(2+), Zn(2+), and Mn(2+) and pH 5.5 for Ni(2+) at 30 °C; agitation speed 150 rpm; contact time 30 min for Mn(2+) and Ni(2+), 30–60 min for Pb(2+), and 90–180 min for Zn(2+); NRCC6 biomass dosage 5.0 g/L for Ni(2+) and Pb(2+) and 10.0 g/L for Mn(2+) and Zn(2+); and initial concentration 12 mg/L of each ion in the multimetal aqueous solutions. Under these optimized conditions, the adsorption capacity for Pb(2+), Ni(2+), Mn(2+), and Zn(2+) reached 98.75, 59.25, 58.33, and 50.83%. The Langmuir isotherm was the best for describing the adsorption of Zn(2+) (0.970) and Mn(2+) (0.977). The Freundlich isotherm significantly giving a good fit to the adsorption of Pb(2+) (0.998) while the adsorption of Ni(2+) onto NRCC6 biomass can follow DKR (0.998). Furthermore, the current study revealed that Mucor sp. NRCC6 fungus is a new efficient and eco-friendly method that revealed a maximum removal of 100% for Pb(2+) and Zn(2+) as well as 97.39, 88.70, 78.95, 74.0, 70.22, 68.57, and 60.0% for Ni(2+), Mn(2+), Cd(2+), Cu(2+), Fe(3+), As(2+), and Cr(6+) from the industrial wastewater, respectively.