# Guide for Optimization of Olive Leaf Extraction and Silver Nanoparticles Biosynthesis as an Initial Step for Pilot Plant Design

## TL;DR

This paper optimizes olive leaf extraction and silver nanoparticle synthesis for potential industrial application.

## Contribution

The study introduces optimized parameters for extraction and biosynthesis using the Box–Behnken design and validates them at a pilot scale.

## Key findings

- Optimal extraction conditions yielded 160.67 μg GAE/mL with high regression accuracy (R² = 0.9936).
- AgNPs synthesis reached a maximum yield of 1.955 under optimized conditions (R² = 0.9757).
- Pilot-scale AgNPs biosynthesis was successfully designed based on the optimized parameters.

## Abstract

This account presents the results of two successful optimization
processes. First, a polyphenol-rich aqueous olive extract was obtained
and then silver nanoparticles (AgNPs) synthesized with high efficiency.
Selected parameters for both processes were optimized based on the
procedure of the Box–Behnken multifactorial design. The independent
variables in the extraction process were the biomass/water ratio,
temperature, and time. For AgNPs synthesis, the independent variables
were the volume of olive extract, temperature, and process duration.
The relationship between the process parameters was visualized graphically
by using the response surface methodology. A high fit of the experimental
data with the predicted models was shown. The regression coefficients
were high, 0.9936 for extraction and 0.9757 for AgNPs biosynthesis.
The extraction efficiency under its optimal conditions was as follows:
biomass/solvent ratio 0.016, temperature 80 °C for 80 min, and
yield 160.67 [μg GAE (gallic acid equivalent)/mL]. The highest
yield of AgNPs synthesis, equal to 1.955, was obtained when it was
carried out for 50 min at 75 °C with the application of 11 mL
of extract. Studies on the AgNPs suspension’s stability depending
on the extract amount were demonstrated. A physicochemical analysis
using dynamic light scattering, transmission electron microscopy images,
and Fourier transform infrared spectroscopy for AgNPs obtained under
optimal conditions was shown. Finally, a pilot-scale biosynthesis
of AgNPs was designed.