title: Biological synthesis of nanosized sulfide semiconductors: current status and future prospects.
abstract: There have been extensive and comprehensive reviews in the field of metal sulfide precipitation in the context of environmental remediation. However, these works have focused mainly on the removal of metals from aqueous solutions-usually, metal-contaminated effluents-with less emphasis on the precipitation process and on the end-products, frequently centering on metal removal efficiencies. Recently, there has been an increasing interest not only in the possible beneficial effects of these bioremediation strategies for metal-rich effluents but also on the formed precipitates. These metal sulfide materials are of special relevance in industry, due to their optical, electronic, and mechanical properties. Hence, identifying new routes for synthesizing these materials, as well as developing methodologies allowing for the control of the shape and size of particulates, is of environmental, economic, and practical importance. Multiple studies have shown proof-of-concept for the biological synthesis of inorganic metallic sulfide nanoparticles (NPs), resorting to varied organisms or cell components, though this information has scarcely been structured and compiled in a systematic manner. In this review, we overview the biological synthesis methodologies of nanosized metal sulfides and the advantages of these strategies when compared to more conventional chemical routes. Furthermore, we highlight the possibility of the use of numerous organisms for the synthesis of different metal sulfide NPs, with emphasis on sulfate-reducing bacteria (SRB). Finally, we put in perspective the potential of these methodologies in the emerging research areas of biohydrometallurgy and nanobiotechnology for the uptake of metals in the form of metal sulfide nanoparticles. A more complete understanding of the principles underlying the (bio)chemistry of formation of solids in these conditions may lead to the large-scale production of such metal sulfides, while simultaneously allowing an enhanced control over the size and shape of these biogenic nanomaterials.
authors.affiliation: Department of Chemistry-CESAM, University of Aveiro, 3810-193, Aveiro, Portugal. jpintocosta@ua.pt.
authors.forename: João Pinto
authors.initials: JP
authors.lastname: da Costa
authors.affiliation: Department of Chemistry-CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Ana Violeta
authors.initials: AV
authors.lastname: Girão
authors.affiliation: Department of Chemistry-CICECO, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Tito
authors.initials: T
authors.lastname: Trindade
authors.affiliation: CCMAR, University of the Algarve, Campus Gambelas, 8005-139, Faro, Portugal.
authors.forename: Maria Clara
authors.initials: MC
authors.lastname: Costa
authors.affiliation: Department of Chemistry-CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Armando
authors.initials: A
authors.lastname: Duarte
authors.affiliation: Department of Chemistry-CESAM, University of Aveiro, 3810-193, Aveiro, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rocha-Santos
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001709:Biotechnology / Q000379:methods* / Q000639:trends; D011232:Chemical Precipitation; D053768:Metal Nanoparticles; D012666:Semiconductors; D013440:Sulfides / Q000378:metabolism*
chemical_list: D013440:Sulfides
keywords: Biological synthesis; Metal sulfides; Nanoparticles