**3. Materials and method**

#### **3.1 Green synthesis of silver nanoparticles**

#### *3.1.1 Preparation of algal biomass*

The cyanobacterial biomass of *P. tenue* was harvested during their exponential phase. After that, the wet algal biomass of *P. teneue* was washed thoroughly with distilled water and ultrasonicated for the green synthesis of the nanoparticle. One gram of ultrasonicated wet biomass was resuspended in 100 mL of 1 mM silver sulfate aqueous solution at pH 7 and incubated in this mixture at 25°C for 24 hours [8, 19] (**Figure 1**).

*Green Synthesis of Silver Nano-Particle from Cyanobacteria and Effect on Microalgal Growth… DOI: http://dx.doi.org/10.5772/intechopen.106039*

**Figure 1.**

*Sequential step for green synthesis of silver nanoparticle from P. tenue [8, 19].*
