Cleaning of water filtration membranes

Patent metadata

Field	Value
Publication number	US-10675589-B2
Application number	US-201615768466-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Oct 14, 2015
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

Methods for cleaning water filtration membranes by treatment with a DNase containing cleaning composition. Optionally the composition also comprises a biocidal and/or other enzymes such as proteases. The DNAse may be derived from Aspergillus oryzae or from Bacillus licheniformis.

First claim

The invention claimed is:

1. A method for cleaning a water filtration membrane, wherein the water filtration membrane comprises a biofilm, the method comprising
i) contacting the membrane with a liquid cleaning composition comprising a DNase and one or more non-DNase enzymes selected from arabinose, carbohydrase, cellulase, cutinase, galactanase, lipase, mannanase, oxidoreductase, pectinase, pectate lyase, perhydrolase, protease and xylanase; or
ii) contacting the membrane with a liquid cleaning composition comprising a DNase, and separately contacting the membrane with one or more non-DNase enzymes selected from amylase, arabinose, carbohydrase, cellulase, cutinase, galactanase, lipase, mannanase, oxidoreductase, pectinase, pectate lyase, perhydrolase, protease and xylanase.

2. The method of claim 1 , wherein the cleaning process is Cleaning-In-Place (CIP) or Cleaning-Out-of-Place (COP).

3. The method of claim 1 , wherein the water flow rate through the membrane (flux) is improved.

4. The method of claim 1 , which is preceded or followed by contacting the membrane with a biocidal composition.

5. The method of claim 1 , wherein the biofilm comprises one or more bacteria selected from the group consisting of Acinetobacter, Bacillus, Comamonas, Escherichia, Pseudomonas , and Sphingomonas species.

6. The method of claim 1 , wherein the biofilm comprises one or more bacteria selected from the group consisting of Acinetobacter calcoaceticus, Bacillus amyloliquefaciens SC100, Bacillus amyloliquefaciens SC168, Comamonas denitrificans, Escherichia coli K-12, Pseudomonas aeruginosa , and Sphingomonas mucosissima.

7. The method of claim 1 , wherein the pH of the cleaning composition is 6-9.

8. The method of claim 1 , wherein the membrane is contacted with the cleaning composition at a temperature between 30-100° C.

9. The method of claim 1 , wherein the DNase is an Aspergillus oryzae DNase or a derivative thereof.

10. The method of claim 1 , wherein the DNase is a polypeptide having DNase activity, which comprises or consists of an amino acid sequence having at least 80% sequence identity to the amino acid sequence shown as SEQ ID NO: 1.

11. The method of claim 1 , wherein the DNase is a polypeptide having DNase activity, which comprises or consists of the amino acid sequence shown as SEQ ID NO: 1.

12. The method of claim 1 , wherein the DNase is a Bacillus licheniformis DNase or a derivative thereof.

13. The method of claim 1 , wherein the DNase is a polypeptide having DNase activity, which comprises or consists of an amino acid sequence having at least 80% sequence identity to the amino acid sequence shown as SEQ ID NO: 2.

14. The method of claim 1 , wherein the biofilm comprises Pseudomonas aeruginosa.

15. The method of claim 1 , wherein the pH of the cleaning composition is about neutral.

16. The method of claim 1 , wherein the membrane is contacted with the cleaning composition at a temperature between 50-80° C.

Assignees

• Novozymes As

Inventors

• Hansen Rasmus Rune
• Baker Ethan

Classifications

• C11D3/386

  Preparations containing enzymes {, e.g. protease or amylase} · CPC title

• B01D61/18

  Apparatus therefor · CPC title

• B01D65/02 Primary

  Membrane cleaning or sterilisation {; Membrane regeneration} · CPC title

• B01D61/22

  Controlling or regulating · CPC title

• C02F2303/20

  Prevention of biofouling · CPC title