Biosorption of heavy metals by Saccharomyces cerevisiae: a review.

http://dzumenvis.nic.in/microbes and metals interaction/pdf/metal bioremediation through growing cells.pdf

Metal bioremediation through growing cells.

http://ssu.ac.ir/cms/fileadmin/user_upload/Mtahghighat/tfood/ARTICLES/microb-safety/Significance_of_microbial_biofilms_in_food_industry_a_review.pdf

Significance of microbial biofilms in food industry: a review

Plant growth-promoting bacteria (PGPB) are soil and rhizosphere bacteria that can benefit plant growth by different mechanisms. The ability of some microorganisms to convert insoluble phosphorus (P) to an accessible form, like orthophosphate, is an important trait in a PGPB for increasing plant yields. In this mini-review, the isolation and characterization of genes involved in mineralization of organic P sources (by the action of enzymes acid phosphatases and phytases), as well as mineral phosphate solubilization, is reviewed. Preliminary results achieved in the engineering of bacterial strains for improving capacity for phosphate solubilization are presented, and application of this knowledge to improving agricultural inoculants is discussed.

/pdf/genetics-of-phosphate-solubilization-and-its-potential-2ot8vyerp7.pdf

Genetics of phosphate solubilization and its potential applications for improving plant growth-promoting bacteria

The biogeochemistry and bioremediation of uranium and other priority radionuclides

Biofilm-immobilised Citrobacter sp removed uranyl ion from flows supplemented with glycerol 2-phosphate The metal uptake mechanism was mediated by the activity of a cell-surface bound phosphatase that precipitated liberated inorganic phosphate with uranyl ion as HUO 2 PO 4 4H 2 O at the bacterial surface A modified integrated form of the Michaelis-Menten equation is proposed to describe the removal of metal ion by a columnar bioreactor, where the efficiency of metal removal is semi-quantitatively related to the input flow rate, the total enzyme loading (E 0 ) and the bioreactor activity With biofilm immobilised bacteria, E 0 was further divisible (split) into subparameters of phosphatase titre per bacterium and total biomass surface area Varying the split E 0 and the reaction temperature modified the bioreactor performance The immobilised bacteria retained high metal loads without loss in steady-state activity Accumulated metal was recovered as a concentrated solution

Enzymatically‐mediated uranium accumulation and uranium recovery using a Citrobacter sp. Immobilised as a biofilm within a plug‐flow reactor

A Citrobacter sp. accumulates uranyl ion (UO{sub 2}{sup 2+}) as crystalline HUO{sub 2}PO{sub 4}{center_dot}4H{sub 2}O (HUP), using enzymatically generated inorganic phosphate. Ni was not removed by this mechanism, but cells already loaded with HUP removed Ni{sup 2+} by intercalative ion-exchange, forming Ni(UO{sub 2}PO{sub 4}){sub 2}{center_dot}7H{sub 2}O, as concluded by x-ray diffraction (XRD) and proton induced x-ray emission (PIXE) analyses. The loaded biomass became saturated with Ni rapidly, with a molar ratio of Ni:U in the cellbound deposit of approx. 1:6; Ni penetration was probably surface-localized. Cochallenge of the cells with Ni{sup 2+} and UO{sub 2}{sup 2+}, and glycerol 2-phosphate (phosphate donor for phosphate release and metal bioprecipitation) gave sustained removal of both metals in a flow through bioreactor, with more extensively accumulated Ni. We propose `Microbially Enhanced Chemisorption of Heavy Metals` (MECHM) to describe this hybrid mechanism of metal bioaccumulation via intercalation into preformed, biogenic crystals, and note also that MECHM can promote the removal of the transuranic radionuclide neptunium, which is difficult to achieve by conventional methods. 42 refs., 1 fig., 1 tab.

Fan Lin

Papers

Enzymatically‐mediated uranium accumulation and uranium recovery using a Citrobacter sp. Immobilised as a biofilm within a plug‐flow reactor

Bioaccumulation of nickel by intercalation into polycrystalline hydrogen uranyl phosphate deposited via an enzymatic mechanism