Effects of Single and Mixed Energy Sources on Intracellular Nanoparticles Synthesized by Acidithiobacillus ferrooxidans

Abstract

Effective biosynthesis of magnetite nanoparticles using current technology is challenging. We investigated the synthesis of nanoparticles by Acidithiobacillus ferrooxidans grown on ferrous iron, elemental sulphur, and mixtures of both substrates. A comparison of tests with different doping amounts of elemental sulphur in ferrous-containing medium showed that the addition of 0.25 and 0.5 M elemental sulphur to the medium resulted in an increased delay of microbial growth and ferrous iron oxidation. TEM suggested that the ferrous material was an essential energy source for the synthesis of nanoparticles in cells. TEM results indicated that the different ratios of ferrous and sulphur had no significant effect on the morphology of bacteria and the size of nanoparticles. High-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDX), and X-ray absorption near edge structure (XANES) showed that the nanoparticles were composed of magnetite. For the first time, HRTEM and XANES spectra in-situ characterization was conducted to investigate the nanoparticles that were synthesized by A. ferrooxidans. The findings from this study indicated that the different ratios of ferrous and sulphur had no significant effect on size and shape of nanoparticles synthesized by A. ferrooxidans.

Phenomic and transcriptomic analyses reveal the sequential synthesis of Fe 3 O 4 nanoparticles in Acidithiobacillus ferrooxidans BYM

“…As an acidophilic chemolithoautotroph, A. ferrooxidans can obtain energy from the oxidation of Fe(II) or reduced sulfur for growth ( 26 ). It has been proven that A. ferrooxidans incubated with FeSO 4 ·7H 2 O can produce Fe 3 O 4 nanoparticle, i.e., magnetosome, which is also synthesized by MTB and exhibits potential in medical and biotechnological applications ( 27 ). Magnetosome synthesis in MTB seems to positively respond to the changes in culture conditions, such as FeSO 4 ·7H 2 O concentration, growth time, and magnetic field intensity ( 28 ).…”

Bioinformatics and Transcriptional Study of the Nramp Gene in the Extreme Acidophile Acidithiobacillus ferrooxidans Strain DC

“…Gu et al [55] indicated that the cotransport of H + could lead to a slight decrease of pH on the inner membrane surface, resulting in maintaining the dissolution of iron before its binding to intracellular proteins. The transfer of ferrous iron into cells may be used to synthesize functional materials such as magnetosomes [34,61]. The results showed that AFE_2126 mRNA levels in At.…”

Dispersion of sulfur creates a valuable new growth medium formulation that enables earlier sulfur oxidation in relation to iron oxidation in Acidithiobacillus ferrooxidans cultures

“…Complex regulation networks, influenced by substrate energies and preculture histories, typically drive the mechanisms that lead to diauxic growth or simultaneous substrate consumption behaviors (Narang & Pilyugin, 2007; Okano et al, 2020). Acidithiobacillus ferrooxidans is a key member of the microbial consortia involved in the industrial‐scale bioleaching of copper, and it has been commonly reported to have diauxic behavior on iron and sulfur with a preference for iron oxidation when both sources are present (Beck, 1960; Espejo & Romero, 1987; Ponce et al, 2012; Suzuki et al, 1990; Wu et al, 2019). However, conflicting behaviors from different strains have been reported for these bacteria, as some of the iron‐ and sulfur‐oxidizing strains studied previously thought to have been A. ferrooxidans have been phylogenetically reclassified or have been collection strains that have not been extensively studied (Amouric et al, 2011; Espejo et al, 1988; Falagán & Johnson, 2016; Ghosh & Dam, 2009; Hallberg et al, 2010; Hedrich & Johnson, 2013; Kelly & Wood, 2000; Norris et al, 2020; Ponce et al, 2012; Suzuki et al, 1990; Yarzabal et al, 2004).…”

“…Complex regulation networks, influenced by substrate energies and preculture histories, typically drive the mechanisms that lead to diauxic growth or simultaneous substrate consumption behaviors (Narang & Pilyugin, 2007;Okano et al, 2020). Acidithiobacillus ferrooxidans is a key member of the microbial consortia involved in the industrial-scale bioleaching of copper, and it has been commonly reported to have diauxic behavior on iron and sulfur with a preference for iron oxidation when both sources are present (Beck, 1960;Espejo & Romero, 1987;Ponce et al, 2012;Suzuki et al, 1990;Wu et al, 2019).…”