Heavy metals removal potential of metal tolerant fungal biomass on leather industry effluent and assessment of treated effluent toxicity by in vitro studies

Improper heavy metal-enriched wastewater release has emerged as an important environmental threat. The purpose of this study was to examine the possibility of using filamentous Aspergillus flavus and Aspergillus niger biomass immobilized on banana and pomegranate peels under in vitro conditions to remove pollutants from the effluent of the leather industry. The physicochemical traits were discovered to be above the allowable limits. Fortunately, both fungal species were grown together in the Potato Dextrose Agar (PDA) plate without exhibiting antagonistic traits. Remarkably, the test A. niger and A. flavus immobilized pomegranate peel and banana peel up to 82% as well as 86%, correspondingly. Under various (Set-I to Set-V) experimental conditions, the total dissolved solids (TDS), total solids (TS), biological oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS) content of treated water samples from Set-V and Set-IV were considerably reduced up to 394 and 343 mg L-1, 417 and 356 mg L-1, 122 and 106 mg L-1, 165 and 129 mg L-1, and 403 and 356 mg L-1, respectively. Similarly, the experimental setup Set-V and Set-IV removed the metals such as Cr, Cu, Pd, Cd, Fe, and Zn up to 6.81 and 4.81, 3.64 and 3.44, 1.8 and 1.3, 2.4 and 1.8, 3.1 and 2.7, and 3.9 and 3.2 mg L-1, respectively, from leather industry effluent. According to these results, the treated effluent had a significant reduction in toxicity as shown by the absence or decreased levels of phytotoxicity and cytotoxicity on Vigna radiata and Artemia franciscana larvae, respectively. According to these findings, A. niger and A. flavus immobilized on pomegranate and banana peels have exceptional ability to remove heavy metals and other pollutants from the leather industry effluents.