Aspergillus versicolor mediated biofabrication of zinc phosphate nanosheets for exploring their antimycotic activity and development of alginate-based nanocomposite for enhanced dye degradation

Abstract

The production of novel, suitable, and cost-effective nanocomposites are highly required for its prospective application in the remediation of environmental pollutants and as antimycotic agents. Zinc phosphate nanosheets (ZP-ns) were fabricated by harnessing the exometabolites of Aspergillus versicolor and then incorporated within an alginate biopolymer (ZP-ns@Alg) to improve the biosorptive removal of the methyl orange (M_thO) dye from its aqueous solution. For the very first time, the antimycotic activity of the green synthesized ZP-ns was unveiled. The mycelial growth inhibition was obtained in a dose-dependent manner with significant (P < 0.05) behavior compared to the control plates. The biosorption conditions using ZP-ns@Alg microbeads were optimized using the response surface methodology-based central composite design (RSM-CCD) to maximize the biosorption efficiency. The highest biosorptive efficiency was achieved at pH 4.0, biosorption dosage 0.07 g, contact time 50 min, dye concentration 100 mg/l, and shaking speed 100 rpm. The equilibrium data were more tailored to the pseudo-second order (PS) model with an R² of 0.9955 and a Langmuir isotherm (R² = 0.9945) with a maximum biosorptive capacity (q_max) of 166.95 mg/g and an average R_L value of 0.0003, indicating favorable biosorption. The removal capacity was reduced to ∼90 % after the 6th cycle, which is a robust signal that the developed biosorbent microbeads could be recycled and regenerated for a prolonged time. These results marked the application of ZP-ns as a novel antimycotic agent with excellent activities. Microbeads, made from low-cost biopolymers, can be applied to remediating environmental pollutants from wastewater.