Simulated-Sunlight-Driven Cell Lysis of Magnetophoretically Separated Microalgae Using ZnFe₂O₄ Octahedrons

Abstract

In an effort to help meet the demand for promising renewable sources of energy, research into innovative downstream processing for microalgae biorefineries is actively underway. In the current work, we used octahedrally shaped ZnFe 2 O 4 nanoparticles for both harvesting and disrupting the cells of microalgae. We were able to use ZnFe 2 O 4 octahedrons as magnetic flocculants and celldisruption agents because ZnFe 2 O 4 nanoparticles have both magnetic and photocatalytic properties. The ZnFe 2 O 4 octahedrons, when simply functionalized with the aminosilane N-[3-(trimethoxysilyl)propyl] ethylenediamine, enabled a rapid and energy-efficient harvesting of microalgae. Furthermore, the ZnFe 2 O 4 octahedrons, well-known for having photocatalytic properties superior to those of ZnFe 2 O 4 nanoparticles with other morphologies, were used to lyse the algal cell wall with the aid of H 2 O 2 under simulated sunlight irradiation. We expect microalgae whose cells can be both magnetophoretically separated and lysed by the same ZnFe 2 O 4 nanoparticles to be utilized as bioenergy resources for more efficient downstream processing than is currently available.

New horizons in developing cell lysis methods: A review

“…They synthesized octahedrally shaped ZnFe 2 O 4 nanoparticles that acted as magnetic flocculants and could harvest the microalgae cells and also lyse them. The ZnFe 2 O 4 octahedrons were functionalized with the aminosilane N ‐[3‐(trimethoxysilyl) propyl] ethylenediamine (Seo et al, 2018). In an another work, sharp nanostructures (nano‐knives) were attached to the sidewalls of the filter region in the microfluidic device resulting in harsh mechanical and shear forces on cell membranes and lysis of them.…”

Application of Nanomaterials in the Production of Biomolecules in Microalgae: A Review

“…The use of Fe 3 O 4 -TiO 2 NPs harboring chitosan-coated core-shell structures could obtain a >98% harvest rate of Mychonastes homosphaera (Chlorophyceae) and reach a 96-97% recovery rate of intracellular lutein and lipid [159]. To reduce energy consumption, ZnFe 2 O 4 octahedrons were constructed using a hydrothermal method and then functionalized with amino silane [160]. The resulting ZnFe 2 O 4 magnetic flocculant enhanced algal cell wall lysis by affecting the photocatalytic Fenton reaction under simulated sunlight irradiation with the assistance of H 2 O 2 solvent [160].…”

Mechanisms of strengthening energy and mass transfer in microbial conversion of flue-gas-derived CO2 to biodiesel and biogas fuels

“…Most microalgal species start to accumulate significant amounts of lipid under stress or unfavorable growth conditions [5]. Seo et al [6] found that the lack of nitrogen salt in the solution would promote the synthesis and accumulation of oil in microalgae cells. However, nitrogen starvation significantly reduced the photosynthetic activities of algal cells and thus the overall productivity of algal biomass.…”

“…Many researchers have found that nitrogen starvation was able to promote the synthesis and accumulation of oil in microalgae cells, but reduce the photosynthetic activity of microalgae cells. There is a conflict between CO 2 fixation and lipid accumulation [5,6]. The competition between multiple intracellular reaction pathways and high energy barriers of target products hinder the desirable cascade energy transfer.…”