Impact of magnetic immobilization on the cell physiology of green unicellular algae Chlorella vulgaris

Abstract

Cell immobilization on the magnetic nanoparticles (MNPs) and magnetic harvesting is a novel approach for microalgal cells separation. To date, the effect of these nanoparticles on microalgal cells was only studied over a short period of time. More studies are hence needed for a better understanding of the magnetic harvesting proposes or environmental concerns relating to long-term exposure to nanoparticles. In this study, the impact of various concentrations of MNPs on the microalgal cells growth and their metabolic status was investigated over 12 days. More than 60% reduction in mitochondrial activity and pigments (chlorophyll a, chlorophyll b, and carotenoids) content occurred during the first 6 days of exposure to ≥50 µg/mL nanoparticles. However, more than 50% growth inhibitory effect was seen at concentrations higher than 400 µg/mL. Exposure to MNPs gradually induced cellular adaptation and after about 6 days of exposure to stress generating concentrations (˂400 µg/mL) of IONs, microalgae could overcome the imposed damages. This work provides a better understanding regarding the environmental impact of MNPs and appropriate concentrations of these particles for future algal cells magnetic immobilization and harvesting.

Role of Fucoxanthin towards Cadmium-induced renal impairment with the antioxidant and anti-lipid peroxide activities

“…In recent years, fucoxanthin has been widely investigated due to its powerful antioxidant and free radical scavenging ability [23][24][25]. The apoptosis induced by oxidative stress is one of the primary mechanisms that are in place in regard to the toxic effects of the heavy metal cadmium [26,27]. On the other hand, few reports were published previously on the ameliorative effect of fucoxanthin against the cadmium-induced toxic effects [8,28,29].…”

Optimization of Microalga Chlorella vulgaris Magnetic Harvesting

“…The process is based on the interactions between the magnetic particles and the surface of the microalgae cells. The magnetic particles can attach to the cells via electrostatic forces, hydrogen bonds, acid-base interactions or van der Waals forces, forming magnetic particle–cell bonding [ 23 ]. Key factors affecting the magnetic separation efficiency include cell type and their growth stage, magnetic particle dosage, pH, ions in the cultivation medium, temperature, and gradient of the magnetic field [ 3 ].…”

Microalgae: The Future Supply House of Biohydrogen and Biogas

“…There are also some ways to improve the efficiency of biohydrogen production, such as microalgae-bacteria coupling biohydrogen production, adding sodium bisulfite (NaHSO 3 ), mixotrophic culture (adding sodium acetate as carbon source, producing carbohydrates for dark-fermentation-H 2 production) and immobilization of microalgae cells to improve light utilization (Chen et al, 2016;Ramanan et al, 2016;Lakatos et al, 2017;Wei et al, 2017;Wong et al, 2018;Taghizadeh et al, 2020;Xu et al, 2020). In the process of bacteria-microalgae coupling biohydrogen production, microalgae and bacteria are co-cultured under the condition of sulfur-deficient to improve the biohydrogen production efficiency by shortening the aerobic stage (the presence of bacteria helps to consume oxygen, thus accelerating the entry of anaerobic metabolism stage).…”