Heavy metal remediation system

{
  "publication_number": "US9719096B2",
  "country": "US",
  "kind": "B2",
  "title": "Heavy metal remediation system",
  "abstract": "The invention provides a system of heavy metal sequestration by bacteria. The bacteria expresses the ppk, mt, and/or β-galactosidase (lacZ) genes and can tolerate at least 25 μM mercury, 1,000 μM zinc, 250 μM cadmium, and 3,000 μM Pb. The system allows for facile determination of the presence of heavy metal contaminants in a liquid and the facile collection of the bacteria that has sequestered large amounts of heavy metal. Further provided is a system of gene expression in bacteria that comprises phage and plastid gene expression elements and delivers a particularly high level of protein expression and heavy metal resistance.",
  "claims": [
    "1. A bacterial cell comprising at least one transgenic chelator agent from among β-galactosidase and ppk, which transgenic chelator agent is not a fusion protein and which transgenic chelator agent is engineered for expression from a promoter and at least one from among a 5′-UTR and a 3′-UTR, whereby the chelator agent renders the bacterial cell resistant to mercury concentrations above 20 μM up to about 80 μM (for ppk), mercury concentrations above 20 μM up to about 120 μM (for β-galactosidase), cadmium concentrations above about 20 μM up to about 250 μM, zinc concentrations above about 20 μM up to about 1000 μM, or lead concentrations above about 20 μM up to about 3,000 μM.",
    "2. The bacterial cell of claim 1, wherein the chelator agent coding sequence corresponds to a β-gal gene and where the bacterial cell is resistant between above 20 μM up to about 120 μM mercury, cadmium concentrations above about 20 μM up to about 250 μM, zinc concentrations above about 20 μM up to about 1000 μM, or lead concentrations above about 20 μM up to about 3,000 μM.",
    "3. The bacterial cell of claim 1, wherein the bacterial cell is resistant between above 20 μM up to about 80 μM mercury.",
    "4. The bacterial cell of claim 1, wherein the chelator agent coding sequence corresponds to only a ppk gene.",
    "5. The bacterial cell of claim 4, wherein the bacterial cell is resistant to mercury concentrations above 20 μM up to about 80 μM.",
    "6. The bacterial cell of claim 1 which, when in a liquid environment containing mercury, cadmium, zinc or lead, accumulates the mercury, cadmium, zinc or lead and turns dark in coloring.",
    "7. The bacterial cell of claim 6 which, when in a liquid environment containing mercury, accumulates the mercury and turns dark in coloring.",
    "8. The bacterial cell of claim 1, which, when in a liquid environment containing mercury, cadmium, zinc or lead, it accumulates the mercury, cadmium, zinc or lead, forms aggregates and precipitates.",
    "9. The bacterial cell of claim 1, which, when in a liquid environment containing mercury, accumulates the mercury, forms aggregates and precipitates.",
    "10. The bacterial cell of claim 1, selected from among an E. coli, Pseudomonas, Cyanobacteria and Bacillus cell.",
    "11. The bacterial cell of claim 1, deployed in a mechanical device comprising a filter, for the convenient removal of the bacteria, which bacteria is applied to the device to remove heavy metal from a contaminated liquid.",
    "12. The bacterial cell of claim 2, wherein the ability of β-galactosidase to cleave 5-Bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) is reduced by the presence of mercury, cadmium, lead or zinc.",
    "13. The bacterial cell of claim 1, wherein the chelator agent gene is transcribed from a strong promoter and which gene is optionally flanked by at least one from among a 5′ UTR or a 3′ UTR, all functionally connected, whereby at least between 4,000 and 8,500 copies of stable transcripts per ng total mRNA correspond to the chelator gene.",
    "14. The bacterial cell of claim 13, wherein the promoter is transcriptional constitutive promoter sequence derived from the plastid 16S rrn gene, the optional 5′ UTR transcriptional enhancer element sequence is derived from bacteriophage T7 gene 10 and the optional 3′ UTR is a plastid rps16 gene 3′UTR Rho-independent transcriptional terminator sequence.",
    "15. The bacterial cell of claim 14, wherein both the 5′ UTR and the 3′ UTR are functionally connected to the chelator agent gene.",
    "16. The bacterial cell of claim 15, wherein at least between 6,000 and 7,500 copies of stable transcripts per ng total mRNA correspond to the chelator gene.",
    "17. A kit for detection of heavy metal contamination comprising: a container for fluids, a bacterial cell culture expressing β-galactosidase, ppk, or ml, and an indicator strip showing increasingly dark coloring corresponding to the coloring of the bacterial culture expressing β-galactosidase, ppk, or mt when grown in the presence of increasing concentrations of the heavy metals.",
    "18. The kit of claim 17, wherein the bacterial cell culture expressing mt, expresses mouse mt1 gene.",
    "19. A bacterial cell comprising a transgenic mt chelator agent, which transgenic chelator agent is not a fusion protein and which transgenic chelator agent is engineered for expression from a promoter and at least one from among a 5′-UTR and a 3′-UTR, whereby the chelator agent renders the bacterial cell resistant to mercury above 20 μM up to about 140 μM, cadmium concentrations above about 20 μM up to about 250 μM, zinc concentrations above about 20 μM up to about 1000 μM, or lead concentrations above about 20 μM up to about 3,000 μM, and the transgenic chelator agent is not fusion protein.",
    "20. The bacterial cell of claim 19 resistant to mercury from above 20 μM to about 140 μM."
  ],
  "description_excerpt": "This patent application is a divisional application from U.S. application Ser. No. 12/859,590 filed Aug. 19, 2010 and claims priority from U.S. Provisional Patent Application No. 61/235,624, filed Aug. 20, 2009.\n\nThis invention was made in part with materials developed under U.S. government grant NSF CBET-0755649 awarded by the National Science Foundation. The government may have certain rights in the invention.\n\nField of the Invention\n\nThis invention relates to the field of molecular biology to create genetically modified bacteria resistant to and capable of sequestering and accumulating heavy metals, including mercury, lead, zinc, and cadmium, for bioremediation of contaminated liquids and solids.\n\nDescription of the Background\n\nMetallic chemical elements that have a relatively high density are often referred to as heavy metals. The heavy metals are toxic even at low concentrations. Toxic heavy metals include mercury, cadmium, lead, zinc and silver. Among the heavy metals, mercury, lead, and cadmium are considered particularly toxic.\n\nMercury has been introduced into the environment as a byproduct of industrial and natural processes and can accumulate in soil and sediments in high concentrations. Patra, M. and Sharma A., Bot. Rev. 66:379-422 (2000). In the United States, coal burning power plants emit about 48 tons of mercury annually, while in Asia and Africa coal burning power plants release more than 1500 tons per year. Clean Air Mercury Rule. U.S. Environmental Protection Agency (“EPA”) 2009, Retrieved Feb. 8, 2009 from the EPA website.",
  "cpc": [
    "C12N 15/70",
    "C02F 2101/20",
    "C02F 3/341",
    "C12N 1/20",
    "C12N 15/63",
    "C12Q 1/34",
    "G01N 33/523",
    "G01N 33/84"
  ],
  "ipc": [
    "C12N 15/70",
    "C02F 3/34",
    "C12N 1/20",
    "C12Q 1/04",
    "C12Q 1/34",
    "G01N 33/52",
    "G01N 33/84"
  ],
  "assignees": [
    "Inter American University of Puerto Rico"
  ],
  "inventors": [
    "Oscar N. Ruiz"
  ],
  "filing_date": "2014-05-30",
  "publication_date": "2017-08-01",
  "grant_date": "2017-08-01",
  "priority_date": "2009-08-20",
  "application_number": "US-201414292668-A",
  "family_id": "43607596",
  "cited_by_count": 2,
  "citations": [
    "US20100276373A1",
    "US20060121604A1"
  ]
}