[0000] The present invention provides methods and uses for treating pyropheophytin-containing compositions, particularly in order to remove pyropheophytin therefrom. The compositions are typically plant, algal, or bacterial derived products such as vegetable oils. The method comprises a step of contacting the compositions with an enzyme having pyropheophytinase activity. Also provided are related apparatus and products for performing such methods and uses.
CLAIMS 1. A method for treating a pyropheophytin-containing composition, comprising contacting the composition with an enzyme which is capable of hydrolysing pyropheophytin. 2,. A method according to claim 1, wherein the composition comprises a plant-derived oil. 3. A method according to claim 1 or claim 2, wherein the enzyme comprises a pheophytinase or pheophytin pheophorbide hydrolasen 4. A method according to any preceding claim, wherein the enzyme is derived from Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera, Oiγzo sativa, Zea mays, Nicotiana tabacum, Ostreococcus lucimarhms, Ostreococcus taurii, Physcomitrella patens, Phaeodactylum tricornutum, Chlamydomonas reinhardtii, Triticum aestivum or Micromonas sp. RCC299. 5. A method according to any preceding claim, wherein, the enzyme comprises an amino acid sequence selected from: LPGFGVG (SEQ ID NO:13), DFLGQG (SEQ ID NO: 14), GNSLGG (SEQ ID NO: 15), LVKGVTLLNATPFW (SEQ ED NO: 16), HPAA (SEQ ID NO: 17), EDPW (SEQ ID NO: 18), and SPAGHCPH (SEQ ID NO: 19). 6. A method according to any preceding claim, wherein the enzyme comprises a polypeptide sequence as defined in SEQ ID NO:1, any one of SEQ ID NO:s 4 to 12, or any one of SEQ ID NOs:21 , 23 or 25, or a functional fragment or variant thereof 7. A method according to claim 6, wherein the enzyme comprises a polypeptide sequence having at least 75% sequence identity to SEQ ID NO: I<5> any one of SEQ ID NO:s 4 to 12, or any one of SEQ ID NOs:21, 23 or 25, over at least 50 amino acid residues. 8. A method according to any preceding claim, wherein pyropheophytin in the composition is hydrolysed to form pyropheophorbide. 9. A method according to claim 8, further comprising a step of removing pyropheophorbide from the composition. 10. A method according to claim 9, wherein the method comprises a deodorization step. 11. A method according to claim 9 or claim 10, wherein the method comprises a step of silica treatment. 12. A method according to claim 11 , wherein the method comprises a two or more silica treatment steps. 13. A method according to claim 11 or claim 12, wherein the silica treatment is performed at about 70 to 110<0>C. 14, A method according to any preceding claim, wherein the enzyme which is capable of hydrolysing pyropheophytin is immobilized on a solid support. 15- A method according to any preceding claim, further comprising contacting the composition with an enzyme having chlorophyllase activity. 16. A method according to claim 15, wherein the enzyme having chlorophyllase activity is immobilized on a solid support. 17. A method according to any of claims 2 to 16, wheiein the composition comprises an oil selected from rice bran, soy, canola, palm, olive, cottonseed, com, palm kernel, coconut, peanut, sesame or sunflower oil. 18. A method according to any preceding claim, wherein the concentration of pyropheophytin in the composition is reduced by at least 10% compared to the concentration of pyropheophytin present in the composition before treatment. 19. A process for refining a plant oil, comprising a method as defined in any preceding claim. 20. A process according to claim 19, further comprising a hexane extraction and/or degumming step. 21. Use of a polypeptide having pyropheophytinase activity for removing pyropheophytin contamination from a composition. 22. An apparatus for the enzymatic treatment of a pyropheopytin- containing composition, comprising (a) a plant oil refining apparatus; and (b) a polypeptide having pyropheophytinase activity operably integrated into the plant oil refining apparatus, such that the polypeptide is capable of hydrolyzing pyropheophytin in the composition during refining of the composition. 23. A composition comprising a polypeptide having pyropheophytinase activity immobilized on silica. 24. A polypeptide having a sequence as defined in SEQ ID NO:4, or encoded by a sequence as defined in SEQ ID N0:3, or a functional variant or fragment thereof having pyropheophytinase activity. 25. A composition obtainable by the process or method of any of claims 1 to 20, 26. A method according to any of claims 1 to 18, wherein the enzyme has a pheophytinase to pyropheophytinase activity ratio of less than 80. 27. A polypeptide having a sequence as defined in SEQ ID NO:25, or a functional variant or fragment thereof having pyropheophytinase activity.