title: Released polysaccharides (RPS) from Cyanothece sp. CCY 0110 as biosorbent for heavy metals bioremediation: interactions between metals and RPS binding sites.
abstract: Bioremediation of heavy metals using microorganisms can be advantageous compared to conventional physicochemical methods due to the use of renewable resources and efficiencies of removal particularly cations at low concentrations. In this context, cyanobacteria/cyanobacterial extracellular polymeric substances (EPS) emerge as a valid alternative due to the anionic nature and particular composition of these polymers. In this work, various culture fractions of the unicellular cyanobacterium Cyanothece sp. CCY 0110 were employed in bioremoval assays using three of the most common heavy metal pollutants in water bodies-copper, cadmium, and lead-separately or in combined systems. Our study showed that the released polysaccharides (RPS) were the most efficient fraction, removing the metal(s) by biosorption. Therefore, this polymer was subsequently used to evaluate the interactions between the metals/RPS binding sites using SEM-EDX, ICP-OES, and FTIR. Acid and basic pretreatments applied to the polymer further improve the process efficiency, and the exposure to an alkaline solution seems to alter the RPS conformation. The differences observed in the specific metal bioremoval seem to be mainly due to the RPS organic functional groups available, mainly carboxyl and hydroxyl, than to an ion exchange mechanism. Considering that Cyanothece is a highly efficient RPS-producer and that RPS can be easily separated from the culture, immobilized or confined, this polymer can be advantageous for the establishment/improvement of heavy metal removal systems.
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.|IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.|Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Rua do Campo Alegre, Edifício FC4, 4169-007, Porto, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Mota
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale delle Cascine, 24, I50144, Florence, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Rossi
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale delle Cascine, 24, I50144, Florence, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Andrenelli
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal.
authors.forename: Sara Bernardes
authors.initials: SB
authors.lastname: Pereira
authors.affiliation: Department of Agrifood Production and Environmental Sciences, University of Florence, Piazzale delle Cascine, 24, I50144, Florence, Italy.|Institute of Ecosystem Study (ISE), National Research Council (CNR), Via Madonna del Piano, 10, 50019, Sesto Fiorentino, FI, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: De Philippis
authors.affiliation: i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal. pmtamagn@ibmc.up.pt.|IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135, Porto, Portugal. pmtamagn@ibmc.up.pt.|Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Rua do Campo Alegre, Edifício FC4, 4169-007, Porto, Portugal. pmtamagn@ibmc.up.pt.
authors.forename: Paula
authors.initials: P
authors.lastname: Tamagnini
mesh_terms: D001665:Binding Sites; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D046889:Cyanothece / Q000378:metabolism*; D007854:Lead / Q000378:metabolism*; D019216:Metals, Heavy / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism
chemical_list: D019216:Metals, Heavy; D011135:Polysaccharides, Bacterial; D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead; D003300:Copper
keywords: Bioremediation; Cyanobacteria; Cyanothece; Extracellular polymeric substances (EPS); Heavy metals; Released polysaccharides (RPS)