Impact of Zero-Valent Iron Nanoparticles on Fremyella diplosiphon Transesterified Lipids and Fatty Acid Methyl Esters

Abstract

Efforts to enhance the transformative potential of biofuels is an important step to achieving an environment-friendly and sustainable energy source. Fremyella diplosiphon is an ideal third-generation biofuel agent due to its ability to produce lipids and desirable essential fatty acids. In this study, the impact of Nanofer 25s nanoscale zero-valent iron nanoparticles (nZVIs) on total lipid content and fatty acid composition of F. diplosiphon strains SF33 and B481 was investigated. We observed significant increases (P < 0.05) in the growth of F. diplosiphon treated with 0.2−1.6 mg L −1 Nanofer 25s, indicating that trace concentrations of nZVIs were not toxic to the organism. Chlorophyll a, carotenoids, and phycobiliprotein levels were not altered in F. diplosiphon treated with nZVIs ranging from 0.4 to 1.6 mg L −1 , confirming that these concentrations did not negatively impact photosynthetic efficacy. In addition, Nanofer 25s ranging from 0.2 to 1.6 mg L −1 had an optimal impact on SF33 and B481 total lipid content. We identified significant increases in unsaturated fatty acid methyl esters (FAMEs) from F. diplosiphon Nanofer 25streated transesterified lipids. Theoretical chemical and physical biofuel properties revealed a product with elevated cetane number and oxidative stability for both strains. Scanning electron microscopy and energydispersive X-ray spectroscopy validated the localization of nZVIs. Our findings indicate that Nanofer 25s nZVIs significantly enhance F. diplosiphon total lipid content and essential FAMEs, thus offering a promising approach to augment the potential of the cyanobacterium as a large-scale biofuel agent.

Microalgal Activity and Nutrient Uptake from Wastewater Enhanced by Nanoscale Zerovalent Iron: Performance and Molecular Mechanism

“…A similar observation was reported that the concurrent decreases of ROS and SOD supported the growth improvement with the involvement of 1.5 mg/L of ZnO nanoparticles . Recently, it was demonstrated that nZVI had a superior reducing capacity and hence alleviated the oxidative stress when attaching to microalgal surfacea or entering the cell interior . In addition, MDA and LDH were analyzed to track the extent of microalgal lipid peroxidation and membrane damage conditions.…”

“…The nanoscale zerovalent iron nanoparticles (nZVI), a commonly favorable source of iron, possess several merits potentially resulting from its size being less than 100 nm, such as enhanced bioavailability, easy interaction with microalgal cell surfaces, promotion of iron uptake, and superior ability of being internalized by endocytosis . Additionally, nZVI might react with the extracellular organic matter secreted by the microalgae for ferrous ion generation, which is even more conducive for microalgal absorption .…”

“…The nanoscale zerovalent iron nanoparticles (nZVI), a commonly favorable source of iron, possess several merits potentially resulting from its size being less than 100 nm, such as enhanced bioavailability, easy interaction with microalgal cell surfaces, promotion of iron uptake, and superior ability of being internalized by endocytosis. 21 Additionally, nZVI might react with the extracellular organic matter secreted by the microalgae for ferrous ion generation, which is even more conducive for microalgal absorption. 22 Considering the significance of iron and the advantages that nZVI presents, it is therefore hypothesized that nZVI might have a significant impact on microalgae growth and physiology, further promoting its bioremediation and nutrient uptake from wastewater.…”

Zero-Valent Iron Nanoparticles Induce Reactive Oxygen Species in the Cyanobacterium, Fremyella diplosiphon

“…16 In recent years, iron nanoparticles, specifically nZVIs, have been applied to boost biomass production in cyanobacteria, and their impact on lipids and fatty acid methyl esters have been reported. 5,17 While the impact of iron deficiency and strategies to cope with this challenge have been extensively studied in other cyanobacteria species, 2 there is still insufficient knowledge of the impact of excessive iron on ROS generation in F. diplosiphon.…”

“…Various stressors such as ultraviolet radiation, high light intensity, and salinity are reported to increase oxidative stress by several folds, leading to cyanobacterial toxicity. , It is well known that in cyanobacteria, iron homeostasis is tightly controlled by the ferric uptake regulator which modulates the transcription of iron-responsive genes . In recent years, iron nanoparticles, specifically nZVIs, have been applied to boost biomass production in cyanobacteria, and their impact on lipids and fatty acid methyl esters have been reported. , While the impact of iron deficiency and strategies to cope with this challenge have been extensively studied in other cyanobacteria species, there is still insufficient knowledge of the impact of excessive iron on ROS generation in F. diplosiphon.…”