Metal adsorption of the polysaccharide produced from Methylobacterium organophilum

Kim, Sang-Yong; Kim, Jung-Hoe; Kim, Chul-Jai; Oh, Deok‐Kun

doi:10.1007/bf00128585

Cited by 94 publications

(32 citation statements)

References 10 publications

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“…The rate constants (k) for Cd(II) over the range of initial concentrations were higher than those for Cu(II). The patterns were observed in line within 50 min, indicating a correlation with the characteristics of inert biomass and its physicochemical interactions with the metal ion (Kim et al, 1996;Sar et al, 1999). The rapid metal sorption is also highly desirable for successful deployment of the biosorbents for practical applications (Sar et al, 1999;Volesky, 1990).…”

Section: Biosorption Kineticsmentioning

confidence: 77%

Biosorptive capacity of Cd(II) and Cu(II) by lyophilized cells of Pseudomonas stutzeri

Hassan

Kim

Jung

et al. 2009

J. Gen. Appl. Microbiol.

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Section: Biosorption Kineticsmentioning

confidence: 77%

Biosorptive capacity of Cd(II) and Cu(II) by lyophilized cells of Pseudomonas stutzeri

Hassan

Kim

Jung

et al. 2009

J. Gen. Appl. Microbiol.

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“…One potential mechanism is complexation or sequestration of divalent metal cations by the EPS and cells at the biofilm-bulk liquid interface. EPS and polysaccharides isolated from EPS have been reported previously to bind heavy metals (19,21,27), in particular Cu (5,20,28). Complexation of heavy metals may result in a gradient in the biofilm, with the highest concentration at the periphery and the lowest concentration near the substratum.…”

Section: Discussionmentioning

confidence: 99%

Heavy Metal Resistance of Biofilm and Planktonic Pseudomonas aeruginosa

Teitzel

Parsek

2003

Appl Environ Microbiol

604

373

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A study was undertaken to examine the effects of the heavy metals copper, lead, and zinc on biofilm and planktonic Pseudomonas aeruginosa. A rotating-disk biofilm reactor was used to generate biofilm and freeswimming cultures to test their relative levels of resistance to heavy metals. It was determined that biofilms were anywhere from 2 to 600 times more resistant to heavy metal stress than free-swimming cells. When planktonic cells at different stages of growth were examined, it was found that logarithmically growing cells were more resistant to copper and lead stress than stationary-phase cells. However, biofilms were observed to be more resistant to heavy metals than either stationary-phase or logarithmically growing planktonic cells. Microscopy was used to evaluate the effect of copper stress on a mature P. aeruginosa biofilm. The exterior of the biofilm was preferentially killed after exposure to elevated concentrations of copper, and the majority of living cells were near the substratum. A potential explanation for this is that the extracellular polymeric substances that encase a biofilm may be responsible for protecting cells from heavy metal stress by binding the heavy metals and retarding their diffusion within the biofilm.Heavy metals are ubiquitous and persistent environmental pollutants that are introduced into the environment through anthropogenic activities, such as mining and smelting, as well as through other sources of industrial waste. In fact, over one-half the superfund sites in the United States are contaminated with at least one heavy metal (www.atsdr.cdc.gov). Heavy metals contaminate drinking water reservoirs and freshwater habitats and can alter macro-and microbiological communities (18, 24). The known mechanisms of heavy metal toxicity include inducing oxidative stress and interfering with protein folding and function (30).Bacteria have developed a variety of resistance mechanisms to counteract heavy metal stress. These mechanisms include the formation and sequestration of heavy metals in complexes, reduction of a metal to a less toxic species, and direct efflux of a metal out of the cell (30-33). Pseudomonas aeruginosa is a ubiquitous, environmentally important microbe that may employ many resistance mechanisms, such as the mer operon that reduces toxic Hg 2ϩ to volatile Hg 0 , which then diffuses out of the cell (33). However, in bacteria, efflux systems are a more common resistance mechanism for dealing with heavy metals. One such system is the cop system of Pseudomonas syringae, which contains the structural genes copABCD and is homologous to the pco system in Escherichia coli. The copB and copD genes are involved in the transport of copper across the membrane, while the products of the copA and copC genes are outer membrane proteins that bind Cu 2ϩ in the periplasm, protecting the cell from copper (6, 36). Other types of efflux systems simply pump toxic metal ions out of the cell; these systems include the P-type ATPase cadA, which was first identified in Staphylococcus aureus and...

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“…Their cells are rigid and relatively insensitive to shear forces because of their thick cell wall. The exopolymers or exopolysaccharides (EPS) they form might play a crucial role in metal biosorption, as has been reported for other bacteria (Kim et al 1996;Loaec et al 1997).…”

Section: Introductionmentioning

confidence: 96%

Biosorption of Copper by Paenibacillus polymyxa Cells and their Exopolysaccharide

Acosta

Valdman

Leite

et al. 2005

World J Microbiol Biotechnol

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Biosorption of heavy metals by gram-positive, non-pathogenic and non-toxicogenic Paenibacillus polymyxa P13 was evaluated. Copper was chosen as a model element because it is a pollutant originated from several industries. An EPS (exopolysaccharide)-producing phenotype exhibited significant Cu(II) biosorption capacity. Under optimal assay conditions (pH 6 and 25°C), the adsorption isotherm for Cu(II) in aqueous solutions obeyed the Langmuir model. A high q value (biosorption capacity) was observed with whole cells (q max =112 mgCu g )1 ). EPS production was associated with hyperosmotic stress by high salt (1 M NaCl), which led to a significant increase in the biosorption capacity of whole cells (q max =150 mgCu g )1 ). Biosorption capacity for Cu(II) of the purified EPS was investigated. The maximum biosorption value (q) of 1602 mg g )1 observed with purified EPS at 0.1 mg ml )1 was particularly promising for use in field applications.

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Metal adsorption of the polysaccharide produced from Methylobacterium organophilum

Cited by 94 publications

References 10 publications

Biosorptive capacity of Cd(II) and Cu(II) by lyophilized cells of Pseudomonas stutzeri

Biosorptive capacity of Cd(II) and Cu(II) by lyophilized cells of Pseudomonas stutzeri

Heavy Metal Resistance of Biofilm and Planktonic Pseudomonas aeruginosa

Biosorption of Copper by Paenibacillus polymyxa Cells and their Exopolysaccharide

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