Bioreduction of metal oxides and oxyanions by photosynthetic bacteria
AssigneeBoard of Regents, The University of Texas
InventorsSamuel Kaplan, Mark D. Moore
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Abstract
The invention relates to Proteobacteria that show unusually high level resistance to a wide range of metal oxides and oxyanions and to methods using selected subgroups for efficient reduction of certain metal oxides and oxyanions to the free metal. High level resistance was shown to be affected by growth conditions, and was observed in facultative photoheterotrophs such as Rhodobacter sphaeroides grown either chemoheterotrophically or photoheterotrophically.
Claims26
A method for the reduction of a metal oxide or oxyanion, comprising contacting the metal oxide or oxyanion with a culture of photosynthetic Proteobacterium selected from a group consisting of Rhodobacter and Rhodopseudomonas in an aqueous medium under conditions facilitating reduction of the metal oxide or oxyanion by said Proteobacterium.
A method of reducing a metal or nonmetal oxide or oxyanion in aqueous medium, comprising growing Rhodobacter under suitable aerobic or anaerobic conditions minimal media having a carbon source in a low oxidation state and contacting a sample containing the metal or nonmetal oxide or oxyanion with the Rhodobacter to allow reduction of said oxide or oxyanion by said Rhodobacter.
A method of reducing an oxide or oxyanion of a metal comprising the steps:
- growing R. sphaeroides in an aerobic or anaerobic environment in minimal media:
- contacting the R. sphaeroides with a sample containing a metal oxide or oxyanion under conditions suitable for reduction of the metal oxide or oxyanion by R. sphaeroides:
- and
- isolating a R. sphaeroides cell or R. sphaeroides cell fraction which contains free metal resulting from reduction of said metal oxide or oxyanion.
A method of isolating free metal from a solution containing an oxide or oxyanion of the metal, comprising:
- reducing the metal oxide or oxyanion under conditions suitable for reduction of the metal oxide or oxyanion by the cytoplasmic membrane fraction of R. sphaeroides 2.4.1 (ATCC 55398) to produce free metal;
- accumulating the free metal in said membrane fraction;
- and
- separating the free metal from the membrane fraction in which the free metal has accumulated to obtain substantiality pure metal.
Dependencies are inferred from the claim text.