Study of biosorption of copper and silver by marine bacterial exopolysaccharides

Abstract

Metal bioremediation was studied by biosorption of analytical grade copper Cu(II) and silver Ag(I) by an exopolysaccharide (EPS) produced by marine bacteria from French Polynesia. Colorimetric analysis showed that EPS was composed of neutral sugars, uronic acids, acetate and especially high sulfate amount (29%). Metal biosorption experiments were conducted in batch process. Results showed that the maximum sorption capacities calculated according to Langmuir model were 400 mg g−1 EPS (6.29 mmol g−1) and 256 mg g ) for Cu(II) and Ag(I), respectively. The influence of pH, biosorbent concentration, ionic strength on EPS biosorption capacities was investigated.Results showed that bacterial EPS can be considered as very promising for copper and silver bioremediation. Further development in dynamic and continuous process at the industrial scale will be organized next.

Formation and Physiochemical Properties of Silver Nanoparticles with Various Exopolysaccharides of a Medicinal Fungus in Aqueous Solution

“…Similarly, silver oxide nanoparticles were not found in the AgNPs prepared with microbial EPS (using XRD) in previous studies [ 23 , 38 ]. In contract, mainly silver oxide nanoparticles were found by XRD during the biosorption of silver ions by bacterial EPS at room temperature [ 39 , 40 ]. Such differences may be due to the different experimental conditions especially the temperature since thermal treatment favors the reduction of Ag + to Ag° [ 41 ].…”

Extremophilic Exopolysaccharides: Biotechnologies and Wastewater Remediation

“…Their production is achievable on a commercial scale, and a projection suggests that just with the use of EPS, the concentration of heavy metals from the ecosystem can be diminished from parts per million (ppm) to parts per billion (ppb; Mohite et al, 2017 ). Moreover, Deschatre et al (2015) has given a brief overview of EPS as an efficient bio sorbent of silver, a finding that can be explored further as a potential approach for mining some precious metals from their respective deposits.…”