Process for controlled adsorption and desorption of phosphate from liquids using phosphate-selective proteins

Patent metadata

Field	Value
Publication number	US-12037265-B2
Application number	US-202117153471-A
Country	US
Kind code	B2
Filing date	Jan 20, 2021
Priority date	Jul 20, 2018
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

The present invention provides systems and methods for concentrating and recovering phosphate from samples. The method comprises using immobilized PBP for binding phosphate and a desorption solution having a pH of 11 or greater to recover phosphate from a sample when the phosphate is found at very low detection levels. Further systems and method for removing arsenate for water sources is also provided.

First claim

The invention claimed is:

1. A method of concentrating and recovering phosphate from a sample, the method comprising:
(a) exposing a liquid sample to immobilized phosphate binding protein (PBP) for a sufficient amount of time to bind phosphate to the immobilized PBP within the sample; and
(b) contacting the immobilized PBP with a desorption solution having a pH of 11 or greater to desorb the phosphate from the immobilized PBP, wherein the phosphate is concentrated with the desorption solution.

2. The method of claim 1 , wherein the method further comprises after (a) a wash step with a washing solution at a neutral pH to remove non-specific binding of other ions in the water.

3. The method of claim 1 , wherein the PBP is immobilized on resins or a membrane or expressed on the surface of a bacteria.

4. The method of claim 3 , wherein the PBP is expressed on a bacteria, and the bacteria is E. coli.

5. The method of claim 1 , wherein the PBP is PstS.

6. The method of claim 1 , wherein the volume of the desorption solution can be about 2 to 10 times less than the raw liquid sample.

7. The method of claim 1 , wherein the method further comprises:
(c) reusing the immobilized PBP by
(i) washing the immobilized PBP with a washing solution at a neutral pH between pH 6.8-7.5,
(ii) re-exposing the immobilized PBP with a second sample,
(iii) desorbing the phosphate from the immobilized PBP by exposing the immobilized PBP to desorption solution of pH of 12 or higher, and
(iv) recovering the phosphate in the desorption solution.

8. The method of claim 1 , wherein the volume of the desorption solution is sufficient to concentrate the phosphate to a reliably quantifiable level.

9. The method of claim 8 , wherein the concentration of the phosphate in the sample before step (a) is from about 0-50 μg/L.

10. The method of claim 1 , wherein the method further comprises detecting the phosphate within the desorption solution.

11. The method of claim 1 , wherein the water sample is an environmental water sample or wastewater sample.

12. The method of claim 11 , the environmental water is river water, lake water, pond water, stream water or creek water, or the wastewater sample is domestic wastewater or agricultural wastewater.

13. The method of claim 1 , wherein the desorption solution has a pH of 12 or greater.

14. The method of claim 13 , wherein the desorption solution has a pH of 12.5 or greater, and wherein at least 80% of the phosphate is released from the PBP.

15. A method of concentrating low levels of phosphate in a sample, the method comprising:
(a) exposing a liquid sample to immobilized phosphate binding protein (PBP) for a sufficient amount of time to bind phosphate to the immobilized PBP within the sample; and
(b) desorbing the phosphate from the immobilized PBP by contacting the immobilized PBP with a desorption solution having a pH of 11 or greater wherein the volume of the desorption solution is at least half of the starting sample volume and the phosphate is concentrated to a detectable level.

16. The method of claim 15 , wherein the desorption solution of step (b) is neutralized to a neutral pH with the addition of an acid.

17. The method of claim 16 , wherein (a) the PBP is immobilized on resins, a membrane or bacteria.

18. The method of claim 15 , wherein the PBP is PstS.

19. The method of claim 15 , wherein the concentration of the phosphate in the sample before step (a) is from about 0-50 μg/L.

20. The method of claim 15 , wherein the wherein the desorption solution has a pH of 12 or greater.

Assignees

• Univ Marquette

Inventors

• Mayer Brooke
• Venkiteshwaran Kaushik

Classifications

• B01J20/3475

  in the liquid phase · CPC title

• G01N30/00

  Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography {or field flow fractionation} (G01N3/00, G01N5/00, G01N7/00, G01N9/00, G01N11/00, G01N13/00, G01N15/00, G01N17/00, G01N19/00, G01N21/00, G01N22/00, G01N23/00, G01N24/00, G01N25/00, G01N27/00, G01N29/00 take precedence) · CPC title

• C12Q1/00

  Measuring or testing processes involving enzymes, nucleic acids or microorganisms (measuring or testing apparatus with condition measuring or sensing means, e.g. colony counters, C12M1/34); Compositions therefor; Processes of preparing such compositions · CPC title

• G01N30/88

  Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 · CPC title

• G01N30/06

  Preparation · CPC title