Laccase enzyme and use thereof
The present invention relates to a novel laccase enzyme obtainable from the strains of genus Thielavia . The invention relates also to the nucleic acid sequence encoding the enzyme, a recombinant host into which the nucleic acid sequence has been introduced and a method for the production of the enzyme in a recombinant host. The enzyme of the invention is suitable for several applications, in particular for increasing the lightness of denim.
1. A recombinant polypeptide having laccase activity, characterized in that it consists of the amino acid sequence SEQ ID NO: 12 or a sequence showing at least 90% identity over the entire length of sequence SEQ ID NO: 12, wherein an enzyme treatment for increasing lightness of desized denim is carried out at temperature 30-80° C.
2. The polypeptide according to claim 1 , wherein the polypeptide is obtainable from genus Thielavia.
3. The polypeptide according to claim 1 , wherein the polypeptide is encoded by the sequence in pALK1342 deposited in E. coli RF5473 under the number DSM 15484.
4. The polypeptide according to claim 1 , wherein optimum pH for laccase activity is at pH 3.5 to 8.
5. The polypeptide according to claim 4 , wherein pH optimum for the laccase activity is about pH 5.5.
6. The polypeptide according to claim 1 , wherein the polypeptide is produced in a host of the genus Trichoderma or Aspergillus.
7. The polypeptide according to claim 1 , wherein an enzyme treatment for increasing lightness of desized denim is carried out by a single treatment and the lightness of denim is increased at least as many units as denim treated by sodium hypochlorite.
8. The polypeptide according to claim 7 , wherein the sodium hypochlorite treatment is carried out in the presence of 25 ml/l of 10% sodium hypochlorite (NaOCI) solution for 15 minutes, at the temperature 40° C., at pH above 10.5, in liquor ratio about 1:15, by using equipment normally used in wet processes in textile industry.
9. The polypeptide according to claim 7 , wherein the laccase treatment is carried out in the presence of one or more mediators.
10. The polypeptide according to claim 7 , wherein the enzyme treatment of denim does not cause any essential strength loss.
11. The polypeptide according to claim 7 , wherein the enzyme treatment of denim does not cause the loss of abraded look.
12. The polypeptide according to claim 1 , wherein the laccase activity is effective in stain removal.
13. The polypeptide according to claim 1 , wherein the laccase activity decolorizes dyes.
14. A nucleic acid sequence, characterized in that it encodes the polypeptide as defined in claim 1 .
15. A vector, characterized in that it comprises the nucleic acid sequence according to claim 14 .
16. The vector according to claim 15 , wherein the nucleic acid sequence has been operably linked to expression control sequences allowing expression in prokaryotic or eukaryotic host cells.
17. A host cell, characterized in that or the vector according to claim 15 has been introduced into the host cell.
18. The host cell according to claim 17 , wherein the host cell is a microbial host cell.
19. The host cell according to claim 18 , wherein the host cell belongs to the genus Trichoderma or Aspergillus.
20. A process for the production of a polypeptide having laccase activity, comprising the steps of culturing the host cell of claim 17 , and recovering the polypeptide.
21. A polypeptide having laccase activity further being obtainable by the process according to claim 20 .
22. A process for obtaining an enzyme preparation comprising a polypeptide of claim 21 said process comprising the steps of culturing a host cell and either recovering the polypeptide from the cells or separating the cells from the culture medium and obtaining the supernatant.