PbS biomineralization using cysteine: Bacillus cereus and the sulfur rush

Abstract

Bacillus sp. Abq, belonging to Bacillus cereus sensu lato, was isolated from an aquifer in New Mexico, USA and phylogenetically classified. The isolate possesses the unusual property of precipitating Pb(II) by using cysteine, which is degraded intracellularly to hydrogen sulfide (H2S). H2S is then exported to the extracellular environment to react with Pb(II), yielding PbS (galena). Biochemical and growth tests showed that other sulfur sources tested (sulfate, thiosulfate, and methionine) were not reduced to hydrogen sulfide. Using equimolar concentration of cysteine, 1 mM of soluble Pb(II) was removed from Lysogeny Broth (LB) medium within 120 h of aerobic incubation forming black, solid PbS, with a removal rate of 2.03 µg L−1 h−1 (∼8.7 µM L−1 h−1). The mineralogy of biogenic PbS was characterized and confirmed by XRD, HRTEM, and EDX. Electron microscopy and electron diffraction identified crystalline PbS nanoparticles with a diameter <10 nm, localized in the extracellular matrix and on the surface of the cells. This is the first study demonstrating the use of cysteine in Pb(II) precipitation as insoluble PbS and it may pave the way to PbS recovery from secondary resources, such as Pb-laden industrial effluents.

Bioremediation of a polymetallic, arsenic-dominated reverse osmosis reject stream

“…2009; Staicu et al . 2019, 2020b). Metal sulphides are sparingly soluble and have high stability (Rumble 2018), therefore precipitate out from solution as non‐toxic biominerals.…”

“…S2). Several bacterial enzymes could be involved in cysteine degradation to H 2 S such as cysteine desulfurase, cystathionine b-synthase and cysteine desulfhydrase (reviewed by Mihara and Esaki 2002;Staicu et al 2020b). In a follow up study, the enzymatic degradation of cysteine will be investigated, alongside the repertoire of carbon source utilization, other than lactate.…”

Comparing Bioeconomy Potential at National vs. Regional Level Employing Input-Output Modeling

“…Sectors such as construction, tourism, or travel services were not analyzed. Nor did this study examine in detail the technological aspects of biomass production and recovery options, e.g., resource recovery associated with coal-combustion streams and the recovery of metals from metal-laden effluents [67]. This may be a consideration for further planned research.…”

Adaptation of Cupriavidus metallidurans CH34 to Toxic Zinc Concentrations Involves an Uncharacterized ABC-Type Transporter

“…Metal homeostasis is important for all bacteria since they have to react swiftly to both the scarcity and excess of either essential or toxic metals [1][2][3]. To defend themselves against high metal toxicity, bacteria depend on multiple resistance mechanisms, including efflux pumps, proteins changing the oxidation state of metals, and intra-or extracellular sequestration of metals [4][5][6][7]. In addition, extracytoplasmic function (ECF) sigma factors play an important role in the response to environmental stressors as well as in metal homeostasis [8].…”