Acidithiobacillus ferrooxidans, a chemolithoautotrophic iron- and sulfur-oxidizing acidophile, is a key contributor to industrial-scale copper metal bioleaching. These cells naturally produce magnetosomes, and they may serve as an emerging platform for magnetosome bioproduction, as magnetotactic bacteria (MTB) are difficult to cultivate and genetically modify. Here, we manipulated the expression of the endogenous homologues to the magA and mamB genes in A. ferrooxidans, which are implicated in iron transport required for magnetosome synthesis. Modulation of mamB had no impact on cell behavior. Overexpression of magA increased magnetosome formation and magnetic responsiveness, and these effects were attenuated by CRISPRi knockdown of magA. The augmented magnetosome formation in the magA overexpression cells also led to enhanced bioleaching of pyrite, which is weakly paramagnetic, and this could be further enhanced by the addition of an external magnetic field. These results confirm that magA plays a critical role in magnetosome formation in A. ferrooxidans and that the magnetosome expression can be enhanced through genetic engineering. In addition, these results demonstrate the potential to improve metal sulfide bioleaching through manipulation of genes involved in magnetosome formation.

**Abstract:** This paper presents a novel approach to enhancing lithium recovery from black powder waste generated during lithium-ion battery recycling. We propose the utilization of genetically optimized *Acidithiobacillus ferrooxidans* strains within a microfluidic reactor system coupled with dynamic pH control. This integrated system leverages the inherent bioleaching capabilities of *A. ferrooxidans* while concurrently addressing limitations associated with traditional bioleaching processes. Specifically, we focus on enhancing lithium solubility and extraction efficiency through engineered metabolic pathways and precise control of environmental parameters, leading to a projected 35% improvement in lithium recovery compared to conventional methods and reduced overall process time by 20%.

The continuous demand for lithium-ion batteries (LIBs) in consumer products and electric vehicles (EVs) has raised concerns about their environmental impact when not disposed of properly. Among the co...

**Abstract:** This paper details a novel, highly efficient method for recovering valuable trace metals (silver, palladium, indium, gallium) from end-of-life photovoltaic (PV) solar panels using a bioleaching process enhanced by magnetically separable nanoparticle catalysts. Leveraging *Acidithiobacillus ferrooxidans* bacterial strains, combined with iron oxide nanoparticles functionalized with chelating ligands, we achieve significantly improved metal extraction kinetics and selectivity compared to traditional bioleaching approaches.

The continuous demand for lithium-ion batteries (LIBs) in consumer products and electric vehicles (EVs) has raised concerns about their environmental impact when not disposed of properly. Among the components of a spent LIB, the recovery of heavy metals, such as nickel, manganese, and cobalt, from cathode materials is the most critical. While biohydrometallurgy is a promising method for this recovery, it relies on large quantities of chemicals such as iron sulfate (FeSO4) as the energy source, which can limit its scalability. In this work, we seek to develop a modified biohydrometallurgy process that is less dependent on external chemical fuels. For this purpose, we examined the feasibility of replacing the FeSO4 salt with metallic iron (Fe) or stainless steel (SS), which is readily available in spent batteries as protective cases. The modification of the culture growth through the utilization of abundant metallic Fe or SS is expected to lower costs and limit chemical transportation, which will likely decrease potential detrimental environmental impacts in comparison with other recycling methods. The growth profile of the autotrophic bacterium Acidithiobacillus ferrooxidans (Atf) was studied after the initial acidification with H2SO4 or HCl. The resulting culture was then used to leach model cathode materials made of NMC622 (Ni/Mn/Co = 6:2:2). Near-unity leaching efficiencies were measured on all four elements of interest, Li, Ni, Mn, and Co, when compared with those by aqua regia-based digestion. This new bioleaching process opens the door to efficiently recovering cathode metals while further simplifying the cultivation process, promising scaled-up applications.

Acidithiobacillus spp. have traditionally been utilized to extract metals from mineral ores through bioleaching. This process has recently expanded to include artificial ores, such as those derived fr...

Acidithiobacillus spp. have traditionally been utilized to extract metals from mineral ores through bioleaching. This process has recently expanded to include artificial ores, such as those derived from municipal solid waste incineration (MSWI) residues. Previous studies have indicated that microbial adaptation enhances bioleaching efficiency, prompting this study to identify proteins involved in the adaptation of A. ferridurans to MSWI residues. We employed data-independent acquisition-parallel accumulation serial fragmentation to determine the proteomic response of A. ferridurans DSM 583 to three distinct materials: bottom ash (BA), kettle ash (KA), and filter ash (FA), which represent typical MSWI residues. Our findings indicate that, irrespective of the residue type, a suite of membrane transporters, porins, efflux pumps, and specific electron and cation transfer proteins was notably upregulated. The upregulation of certain proteins involved in anaerobic pathways suggested the development of a spontaneous microaerobic environment, which minimally impacted the bioleaching efficiency. Additionally, the adaptation was most efficient at half the target FA concentration, marked by a significant increase in the detoxification and efflux systems required by microorganisms to tolerate high heavy metal concentrations. Given that metal recovery peaked at lower FA concentrations for most metals of interest, further adaptation at the level of protein expression may not be warranted for improved bioleaching outcomes.