*2.2. Alkaline Treatment of C. pentandra Fiber*

This treatment process was performed using an alkaline solution of sodium hydroxide (NaOH). The mass of 2.0 g of untreated *C. pentandra* fiber and 200 mL of 1.0 M NaOH (1:100) was mixed in the 500 mL beaker as shown in Figure 2a. The mixture was soaked for 5 h at a temperature of ~90 ◦C. After the soaking process, the NaOH treated *C. pentandra* fiber was washed extensively with distilled water until the pH becomes neutral (pH 7) using pH meter. The washed NaOH treated *C. pentandra* fiber was then dried in an oven at 60 ◦C overnight. The NaOH treated *C. pentandra* fiber was stored in a plastic container at room temperature until further usage. The NaOH treated *C. pentandra* fiber was referred to as "treated *C. pentandra* fiber" hereafter.

**Figure 2.** (**a**) Alkaline treatment of *C. pentandra* fiber and (**b**) in-situ biofabrication of Ag-NPs using *E. spiralis* extract and AgNO3 solution steps of preparation.
