2.3.2. Green Synthesis of MgO-NPs

Approximately 102.5 mg of Mg(NO3)2·6H2O was dissolved in 10 mL dis. H2O, then mixed with 90 mL of fungal biomass filtrate overnight to produce a final concentration of 4 mM. At the end of the incubation period, the Mg(OH)<sup>2</sup> was formed as turbid white precipitate, which was collected and rinsed with dis. H2O to remove any impurities before being oven-dried at 100 ◦C for 1 h (Equation (1)).

$$\text{Mg(NO}\_3\text{)}\_2\cdot6\text{H}\_2\text{O} + \text{H}\_2\text{O} \overset{\text{Fungal}}{\underset{\text{Metabolic}}{\rightarrow}} \text{Mg(OH)}\_2\tag{1}$$

The formed Mg(OH)<sup>2</sup> was calcinated at 400 ◦C for 3 h to form MgO-NPs, as represented in Equation (2) [31]. The controls including fungal biomass filtrate and Mg(NO3)2·6H2O solution ran alongside the experiment under the same conditions.

$$\text{Mg(OH)}\_{2} \stackrel{400^{\circ}\text{C}}{\rightarrow} \text{MgO} \tag{2}$$
