Method for biodegrading high molecular weight polycyclic aromatic hydrocarbon pyrenes with halophilic bacteria
A method and composition for biodegrading or bioremediating a pyrene or other polycyclic aromatic hydrocarbon (“PAH”) with one or more bacteria of the genus Halomonas or Idiomarina . Bacterial strains useful for degrading or remediating pyrenes and other polycyclic aromatic hydrocarbons.
1. A method for degrading a polycyclic aromatic compound (PAH) comprising:
pumping groundwater or other liquid contaminated with one or more PAHs into a bioreactor to which one or more bacteria of the genus Halomonas have been added,
contacting said groundwater or other liquid in the bioreactor with the one or more bacteria in a medium containing NaCl at a temperature of at least 15° C. for a time sufficient to degrade the PAH;
wherein said Halomonas have 16s ribosomal RNA that is at least 95% identical to SEQ ID NO: 1.
2. The method of claim 1 , wherein said contacting occurs at a pH of less than pH 7 and at a temperature of at least 25° C. and in the presence of at least 5 wt % NaCl and the PAH comprises pyrene.
3. The method of claim 1 , wherein said contacting occurs at a pH of at least 7 in a groundwater or other liquid solution at a temperature of at least 25° C. and in the presence of at least 5 wt % NaCl.
4. The method of claim 1 , wherein the PAH is pyrene (PYR).
5. The method of claim 1 , wherein the PAH is naphthalene (NAPH), anthracene (ANT), or phenanthrene (PHEN).
6. The method of claim 1 , wherein said contacting occurs in an aqueous solution at a temperature of at least 37° C.
7. The method of claim 1 , wherein the contacting occurs in an aqueous solution containing at least 10 wt. % NaCl.
8. The method of claim 1 , wherein said contacting occurs in the presence of pyrene at an acidic pH and at a temperature ranging from 25 to 37° C. and the NaCl is present in an amount of 10-20 wt. % to form a mixture comprising 4-phenanthrenecarboxylic acid, 4-(1-hydroxynaphthalen-2-yl)-2-oxo but-3-enoic acid, and phthalic acid.
9. The method of claim 1 , wherein the Halomonas is attached to a carrier.
10. The method of claim 1 , further comprising providing one or more non-PAH carbon sources for Halomonas during said contacting.
11. The method of claim 1 , wherein said bioreactor comprises a system of mechanical or electronic elements that process and control the flow and exposure of a material containing a PAH to the Halomonas bacteria.
12. The method of claim 1 , wherein said groundwater or other liquid is contained in soil, sludge or in or on another solid or semisolid material.
13. The method of claim 1 , wherein said contacting occurs in a biopile which is heated electrically.
14. The method of claim 1 , further comprising:
contacting the PAH with Halomonas smyrnensis having 16s ribosomal RNA that is at least 95% identical to SEQ ID NO: 2 and that degrades PAH and/or with Idiomarina piscisalsi having 16s ribosomal RNA-encoding DNA sequence that is at least 95% identical to SEQ ID NO: 4 and that degrades PAH.
15. The method of claim 1 , further comprising growing the Halomonas in an artificial culture medium to a titer of at least 10 6 CFU/ml prior to adding to the bioreactor.
16. The method of claim 1 , wherein said Halomonas have a doubling time of no more than 24 hours in a medium containing 50 ppm pyrene.
17. The method of claim 1 , wherein said groundwater or contaminated liquid further contains or is admixed with at least one of crude oil, diesel fuel or lubricating oil.
18. The method of claim 1 , wherein said groundwater or contaminated liquid further contains or is admixed with at least one of octane, decane, hexadecane, methylcyclopentane, methylcyclohexane, heptamethylnonane, benzene, toluene, ethylbenzene, m-, o- and p-xylenes, and carbazole.
19. The method of claim 1 , wherein said Halomonas is mixed with a carrier or bulking agent selected from the group consisting of agricultural waste, tree litter, grain or maize husks or cobs, bagasse, bark, post peelings, fruit waste, stones, or a mixture thereof.