Immobilized fungi in commercial polyurethane foam removes short-time phosphorus from domestic effluents

Abstract

Summary: Eutrophication drives water contamination, and the primary responsible pollutant is phosphorus in hydric systems. Based on phosphatase (EC 3.1.3.2) capacity to convert organic phosphorus into inorganic compounds, the power of phosphatase production in four fungal isolates and the potential of these organisms trapped in polyurethane foams to remove phosphorus from domestic effluents were investigated. The fungal biomass was grown in a minimal medium plus potassium (1 and 4 g L−1) containing blocks (0.71 mm3) of commercial polyurethane foam. A 32 factorial design was set up to verify the influence of immobilization time and foam supply on phosphatase production by the fungi. Thereafter, the effects of reaction time and volume of domestic effluent were simultaneously evaluated. All fungi produced more phosphatase after immobilization by entrapment. The isolates Aspergillus niger, and A. flavus had higher phosphatase activity (229 µmol h−1) after 192 and 96 h of growth, respectively. Based on the rotational central composite planning, the two independent variables were identified as significant factors (p<0.05) to produce phosphatases, and the maximum activity was obtained with 96 h of immobilization and 9 foam blocks for A. flavus, 72 h of immobilization and 12 blocks for Talaromyces pinophilus and Trichoderma asperellum, and 72 h of immobilization and 15 blocks for A. niger. The immobilized system of A. flavus, A. niger, and T. asperellum could remove 99.9% of the phosphorus in 1 h 10 m, while that of T. pinophilus removed phosphorus at 2 h after incubation with the domestic effluent. Overall, all fungal isolates are potential bioremediators of phosphorus in domestic effluents.

Keywords

• Cell immobilization
• Pollution microbiology
• Mycoremediation