WO2016081239A1

WO2016081239A1 - Remediation of sulfate reducing bacteria with specific bacteriocin

Info

Publication number: WO2016081239A1
Application number: PCT/US2015/060119
Authority: WO
Inventors: Christopher JANES; Elizabeth J. Summer; Abhiram THATIPELLI
Original assignee: Dow Global Technologies Llc
Priority date: 2014-11-18
Filing date: 2015-11-11
Publication date: 2016-05-26
Also published as: AR102575A1

Abstract

The invention relates to a composition and methods for remediation of sulfate reducing bacteria (SRB) with newly discovered broad range bacteriocin recovered from oil and gas operation waste waters.

Description

REMEDIATION OF SULFATE

REDUCING BACTERIA WITH SPECIFIC BACTERIOCIN

Background

Field

[0001] The field of this invention is remediation of sulfate reducing bacteria (SRB). Specifically it is a composition and methods for remediation of SRB with newly discovered broad range bacteriocin recovered from oil and gas operation waste waters.

Background

[0002] Microbial influenced corrosion (MIC) and souring are common problems of oil and gas fields. Great microbial population diversity exists in different oil and gas production fields. The reported microorganisms associated with corrosion and souring include (1) sulfate-reducing bacteria (SRB), such as various species of Desulfovibrio; (2) acid-producing bacteria (APB), such as Acetobacterium carbinolicum; (3) iron-reducing bacteria (IRB), such as Shewanella oneidensis and Geobacter sulfurreducens; and (4) methane -producing archaea, such as Methanoplanus petrolearius. It is thought that SRB promote corrosion by consuming hydrogen and inducing the formation of ferrous sulfide and IRB promote corrosion by reductively dissolving the protective ferric oxide coat that forms on the steel surface. APB produce corrosive acids, such as acetate and butyrate, to induced the corrosion.

[0003] The oil and gas industry currently uses a host of biocides to treat microorganisms that cause corrosion and souring. Both oxidizing (chlorine, chloramines) or nonoxidizing biocides (amine-type compounds, anthraquinones and aldehydes) are widely applied within the industry to control microbial populations. Biocide application is not always effective, possibly due to the different identities and physiologies of microorganisms to be controlled in different systems. In addition to their poor effectiveness, the environmental impacts of those chemical biocides are generally considered negative. There are great needs in oil and gas industry to apply less toxic and more effective antimicrobials for corrosion control.

[0004] Some bacterial strains indigenous to oil fields are capable of producing natural antimicrobial substances to combat different surrounding oil field microbial populations. These antimicrobial substances are usually small molecules, including but not limited to bacteriocins, secreted enzymes such as proteases, RNA-degrading or cell wall lytic enzymes. Some of these substances are active only against the same or closely related species while others have a broad activity spectrum. For example, some Bacillus strains were isolated from oil fields and their capabilities of producing antimicrobial substances against other Bacillus strains and SRB were reported (Korenblum E, etc. Production of antimicrobial substances by Bacillus subtilis LFE-1, B. firmus HO-1 and B. lichenif ormis T6-5 isolated from an oil reservoir in Brazil, j Appl Microbiol. 2005; 98(3):667-75.).

[0005] This invention is a method to screen and isolate antimicrobial substances produced by microorganisms indigenous to oil and gas field, and their application in controlling corrosion causing bacteria such as SRB. It is also a composition of a newly identified broad range bacteriocin produced by bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica., Ideonella. and/or other microorganisms recovered from North American oil and gas well waste water.

Summary

[0006] The present invention is a composition and method of use of newly identified broad range bacteriocins produced by bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica., Ideonella and/or other microorganisms isolated from North American oil and gas well waste water.

Description of Figures

[0007] Figure 1 is a picture of zone of interference by the antimicrobial substances on D. desulfuricans.

Detailed Description

[0007] This invention is based on a composition of newly discovered bacteriocin having broad killing range for sulfate reducing bacteria (SRB). Bacteriocins are anti-microbial peptides or proteins produces by bacteria for microbial competition, usually against closely related bacteria. Productions of bacteriocins both by Gram positive bacteria (such as lactic acid bacteria or Bacillus), and by Gram negative bacteria (many members of Enterobacteriaceae family, such as Escherichia coli), have been documented. Some of the documented bacteriocins exhibit broad inhibition spectrum covering many members of Gram positive and Gram negative bacteria. Bacteriocins showing activity against different members of SRB will have great potential for their environmental applications as natural biocides in oil and gas industries. The present invention is based upon newly discovered bacteriocin recovered from a Gram negative bacteria native to oil and gas environments.

[0008] The problems and need for remediation of sulfate reducing bacteria in oils and gas operation waters and in oil and gas reservoirs (production of hydrogen sulfide) are well described in U.S. 8,168,419 issued 05/01/2012 and U.S. 8,252,576, issued 08/28/2012, the disclosures of which are incorporated herein by reference.

[009] The term "unwanted bacteria," as used herein, refers to the strain(s) of bacteria specifically targeted for control by the invention described herein. Typically, but not necessarily, the unwanted bacteria is targeted for control because of interference with the reaction(s), such as in the case of unwanted SRB in oil and gas drilling and production waters such as fracturing water, produced water and water .The unwanted bacteria need not necessarily be known, isolated, or identified; the sole defining characteristic is that it is the organism(s) desired to be controlled. This invention provides for reduction of invasive bacteria and other unwanted and problematic bacteria.

[0010] Effective amount as used herein means an amount sufficient to effect a detectable reduction in targeted unwanted bacteria.

Screening for strains producing antimicrobial substances against oil field SRB

[0011] Several thousand bacteria strains isolated from up to one hundred oil and gas samples were screened for their capabilities to produce substances that kill sulfate reducing bacteria (SRB). The oil and gas samples include fracturing water, produced water, pit water; waste water collected mainly from North American production plants (oil and gas water systems). In detail, these samples were serial diluted and plated onto SRB selecting media plates. After incubation, the grown up individual colonies were picked and transferred onto a fresh plate. The colony leftovers on the original plate were killed by chloroform vapor. The killed plates were overlaid with indicator bacterial lawns freshly made with different SRB, including D. alaskensis, D. desulfuricans, D. longus, D. vulgaris and EBS.14 (a filed isolate from Barnett Shale). After incubation, any zone of inhibition (ZOI) on the indicator SRB lawns was noted and the matching copy of the producing strain (transferred on a separate plate before killing) was purified and identified. The example ZOI picture can be seen in Figure 1. Four strains producing antimicrobial substances, visualized as zone of inhibition (ZOI) on the indicator SRB lawns, were identified. These four strains were designated for identification as EC42.15, EC35.6, EC35.25, and EC37.22, were their identities were determined by 16s rDNA sequencing as Pseudomonas aeruginosa (EC42.15), Thauera aminoaromatica (EC35.6), and Ideonella sp. (37.22). The exact identity of strain EC35.25 was not determined. The antimicrobial substances produced by these four strains showed broad killing spectrum against different SRB strains isolated from oil and gas field (Table 1).

Killing range of antimicrobial substances produced by four strains against different

[0012] The strain showing the broadest killing spectrum, P. aeruginosa EC42.15, was chosen for further characterization.

Characterization and production of the antimicrobial substances produced by P. aeruginosa EC42.15

[0013] The genome of P. aeruginosa EC42.15 was sequenced. The complete bioinformatics analysis of the genome sequence identified DNA regions coding putative antimicrobial proteins. The putative antimicrobial proteins were separated and purified from the culture supernatant of P. aeruginosa EC42.15. The specific activity of each protein against SRB was determined as described above. This information allows designing of efficient production of these proteins for application in controlling SRB of oil and gas industries. The antimicrobial proteins can be expressed in their native host or expressed in a different bacteria host for maximum production rate. Multiple antimicrobial proteins with different SRB killing spectrums can be combined for broader SRB control in oil and gas industry. Method of Use in Oil and Gas Operations

[0014] The bacteriocins described herein are used in oil and gas operation to remediate unwanted bacteria that cause fouling, corrosion and reservoir souring (H₂S production) in the same manner as are other biocides. Very suitable methods as described in described in U.S. 8,168,419 issued 05/01/2012 and U.S. 8,252,576, issued 08/28/2012, the disclosures of which are incorporated herein by reference. The bacteriocin may be added to bacteriophage as well as other biocides. Since the bacteria in oil and gas well is diverse the remediation of a dominate strain may allow a less dominate strain to become dominate. In such case the less dominated may not be killed by the initially applied biocide composition (cocktail) used so that the cocktail composition will need to be changed to remediate the dynamic changing population of unwanted bacteria. The change will be effected base on monitored analysis or timed sequence. A method of accomplishing such dynamic behavior is described in U.S. published application 2014/0273159, published, 09/18/2014, for staged bacteriophage. The same procedures and methods may be applied for the bacteriocin described herein. The bacteriocin may be contained in cocktails with bacteriophage including those described in U.S. published application 2014/0273159, published - 09/18/2014, the disclosure of which is incorporated herein by reference. For example an embodiment the invention is a process for control of a broad range of target bacteria comprising: culturing a dominant group of bacteria in a mixed bacteria solution;

adding bacteriocin isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoawmatica and Ideonella to remove the dominant bacteria from the mix;

culturing the next dominant strain from the solution;

isolating a virulent phage for the next dominate bacteria, adding an effective amount of bacteriocin isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoawmatica and Ideonella to it to remove the next dominate bacteria;

continuing the sequence to provide a set of bacteriocin that will reduce the dominate and sub- dominate bacteria;and

applying an effective amount of the bacteriocin that is so isolated in each step either as a mixture or in sequence application to waters containing a mixture of target bacteria of those found in each step of the above sequence.

[0015] The preferred bacteriocin for the initial stage is that isolated from bacterial strains

Pseudomonas aeruginosa. [0016] While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

1. A composition comprising a bacteriocin having broad range killing activity against sulfate reducing bacteria (SRB) isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella recovered from North American oil and gas well waste water.

2. The composition of claim 1 wherein the bacteriocin is one isolated from Pseudomonas aeruginosa, designated as EC42.15 as described in the specification.

3. The composition of claim 1 comprising the combination of bacteriocin isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella recovered from North American oil and gas well waste water.

4. The composition of claim 2 derived from over-producing system mutants of

Pseudomonas aeruginosa, by natural mutation or genetic manipulation.

5. A method of control of unwanted bacteria in oil and gas water systems by adding an effective amount of bacteriocin isolated from isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella recovered from North American oil and gas well waste water.

6. The method of claim 5 wherein the bacteriocin is isolated from Pseudomonas aeruginosa, designated as EC42.15 as described in the specification.

7. The method of claim 5 comprising contacting unwanted bacteria with Pseudomonas aeruginosa designated EC42.15, as defined in the specification, capable of producing bacteriocin virulent for the unwanted bacteria in a sufficient amount and for sufficient time for the bacteriocin bacteria to produce an effective amount of bacteriocin virulent for unwanted bacteria.

8. The method of claim 5 also comprising contacting unwanted bacteria containing material with bacteriocin(s) other than those isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella that are capable of killing the bacteria SRB.

9. The method of claim 5 wherein the SRB are selected from D. alaskensis, D.

desulfuricans, D. longus, D. vulgaris.

10. The method of claim 6 wherein the SRB are selected from D. alaskensis, D.

desulfuricans, D. longus, D. vulgaris.

11. A process for control of a broad range of target bacteria comprising:

culturing a dominant group of bacteria in a mixed bacteria solution;

adding bacteriocin isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella to remove the dominant bacteria from the mix;

culturing the next dominant strain from the solution;

isolating a virulent phage for the next dominate bacteria, adding an effective bacteriocin isolated from bacterial strains Pseudomonas aeruginosa, Thauera aminoaromatica and Ideonella to it to remove the next dominate bacteria;

continuing the sequence to provide a set of bacteriocin that will reduce the dominate and sub-dominate bacteria; and

applying an effective amount of the bacteriocin so isolated in each step either as a mixture or in sequence application to waters containing a mixture of target bacteria of those found in each step of the above sequence.

12. The process of claim 1 wherein the predominant bacteria(s) in the mixed bacteria solution are sulfate reducing bacteria.