Biosynthesis of Silver Nanoparticles from Synechocystis sp to be Used as a Flocculant Agent with Different Microalgae Strains

Abstract

Background: Biofuels produced from trans-esterification of high lipid content in microalgae represent a promising alternative renewable source of energy to the limited and depleted global fossil fuel reservoir. The most critical step in such a process is the harvesting of algal cells. Objective: We aimed to improve the current methodology for microalgae harvesting via utilizing biosynthesized Silver Nanoparticles (AgNPs) from Synechocystis sp. ElfSCS31 as an eco-friendly, stable, and affordable flocculant agent. Methods: AgNPs were prepared by the green synthesis method using the alcoholic extract of Synechocystis sp. ElfSCS31. The synthesized nanoparticles were characterized by Zeta sizer, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and UV-Vis Spectroscopy. Biosynthesised AgNPs were applied for harvesting on 20 microalgae strains, then harvesting efficiency was determined by UV Spectrophotometry. Results: Our results revealed an average size of polydispersed nanoparticles ranges from 10 to 100 nm for prepared AgNPs and potential of 1.78 mV, with an average crystallite size of 22 nm. Biosynthesised AgNPs exhibited harvesting efficiency towards different strains of microalgae, reached to 97% in some strains as in Chlorella lobophora and Chlorococcum oleofaciens. Conclusion: The presented study introduces a feasible strategy using biosynthesized AgNPs as a flocculant agent to harvest different strains of microalgae at normal growth conditions of light and temperature. Our developed method could replace the classical high-cost step of harvesting that leads to unlocking the full potential of microalgae as a promising and fascinating source for biofuels production.

RETRACTED ARTICLE: In vitro antioxidant, anticancer, anti-inflammatory, anti-diabetic and anti-Alzheimer potentials of innovative macroalgae bio-capped silver nanoparticles

“…Hence, the procurement of biological, safe, available and inexpensive materials with high reducing/stabilizing potentials and production of Ag-NPs with good biological, chemical and physical properties is now a high urgency for medical field. Marine macroalgae such as Galaxaura elongata (G. elongata), Turbinaria ornata (T. ornata) and Enteromorpha flexuosa (E. flexuosa) crude extracts are innovative and promising green reducing and capping agents, and they contain various vitamins, minerals, organic and inorganic ingredients that could help human health (Pádua et al 2004 ; Rao and Boominathan 2015 ; Ramkumar et al 2017 ; Ahmed et al 2020 ; Fathy et al 2020 ; Abdelrheem et al 2021 ; Abdel Azeem et al 2021 ; Mohamed et al 2022 ).…”

Recombinant overexpression of the Escherichia coli acetyl‐CoA carboxylase gene in Synechocystis sp. boosts lipid production

“…CSNPs/pDNA complexes enter cells through either charge‐mediated interactions with negatively charged proteoglycans on the cell surface or receptor‐mediated endocytosis [34], causing coagulation of the microalgal cells (Figure S4). Microalgal cell membranes carry a net negative charge due to deprotonation of the carboxylic groups, thiolate groups, and hydroxyl groups on the membrane surface, so they attract CSNPs [35].…”

Green Synthesis of Silver Nanoparticles by the Cyanobacteria Synechocystis sp.: Characterization, Antimicrobial and Diabetic Wound-Healing Actions

“…for the biosynthesis of nano-metals was reported once by Fathy et al [26], who used an extract of Synechocystis sp. for the in vitro synthesis of AgNPs and used the synthesized nanoparticle as a flocculent agent with different microalgae strains [26]. The cyanobacterium Synechocystis sp.…”