Variants of polypeptides having cellulolytic enhancing activity and polynucleotides encoding same

1. A variant of a parent GH61 polypeptide having cellulolytic enhancing activity, comprising a substitution at one or more positions corresponding to positions 90, 131, 134, and 141 of the full-length polypeptide of SEQ ID NO: 2, wherein the substitution at a position corresponding to position 90 is with Val, the substitution at a position corresponding to position 131 is with Ser, the substitution at a position corresponding to position 134 is with Leu, and the substitution at a position corresponding to position 141 is with Trp, wherein the variant has cellulolytic enhancing activity and increased thermal activity and/or increased thermostability, and wherein the variant has

at least 95% sequence identity to the mature polypeptide of SEQ ID NO: 2.

2. The variant of claim 1 , which comprises one or more substitutions selected from the group consisting of L90V, D131S, M134L, and A141W.

3. The variant of claim 1 , which comprises the substitutions L90V+D131S+M134L+A141W of the mature polypeptide of SEQ ID NO: 2.

4. An isolated polynucleotide encoding the variant of claim 1 .

5. An isolated recombinant host cell transformed with the polynucleotide of claim 4 .

6. A method of producing a variant, comprising:

(a) cultivating the recombinant host cell of claim 5 under conditions suitable for the expression of the variant; and

(b) recovering the variant.

7. A transgenic plant, plant part or plant cell transformed with the polynucleotide of claim 4 .

8. A method of producing the variant of claim 1 , comprising:

(a) cultivating a transgenic plant or a plant cell comprising a polynucleotide encoding the variant under conditions conducive for production of the variant; and

(b) recovering the variant.

9. A method for obtaining a variant of a parent GH61 polypeptide having cellulolytic enhancing activity, comprising introducing into the parent GH61 polypeptide a substitution at one or more positions corresponding to positions 90, 131, 134, and 141 of the full-length polypeptide of SEQ ID NO: 2, wherein the substitution at a position corresponding to position 90 is with Val, the substitution at a position corresponding to position 131 is with Ser, the substitution at a position corresponding to position 134 is with Leu, and the substitution at a position corresponding to position 141 is with Trp, wherein the variant has cellulolytic enhancing activity and increased thermal activity and/or increased thermostability, and wherein the variant has

at least 95% sequence identity to the mature polypeptide of SEQ ID NO: 2.

10. A method for degrading a cellulosic material, comprising: treating the cellulosic material with an enzyme composition comprising the variant of claim 1 .

11. The method of claim 10 , further comprising recovering the degraded cellulosic material.

12. A method for producing a fermentation product, comprising:

(a) saccharifying a cellulosic material with an enzyme composition comprising the variant of claim 1 ;

(b) fermenting the saccharified cellulosic material with one or more fermenting microorganisms to produce the fermentation product; and

(c) recovering the fermentation product from the fermentation.

13. A method of fermenting a cellulosic material, comprising: fermenting the cellulosic material with one or more fermenting microorganisms, wherein the cellulosic material is saccharified with an enzyme composition comprising the variant of claim 1 .

14. The method of claim 13 , wherein the fermenting of the cellulosic material produces a fermentation product.

15. The method of claim 14 , further comprising recovering the fermentation product from the fermentation.

16. A detergent composition comprising the variant of claim 1 and a surfactant.

17. A whole broth formulation or cell culture composition comprising the variant of claim 1 .

18. The variant of claim 1 , wherein the variant has at least 96% sequence identity to the mature polypeptide of SEQ ID NO: 2.

19. The variant of claim 1 , wherein the variant has at least 97% sequence identity to the mature polypeptide of SEQ ID NO: 2.

20. The variant of claim 1 , which comprises a substitution at two positions corresponding to any of positions 90, 131, 134, and 141.

21. The variant of claim 1 , which comprises a substitution at three positions corresponding to any of positions 90, 131, 134, and 141.

22. The variant of claim 1 , which comprises a substitution at each position corresponding to positions 90, 131, 134, and 141.

23. The method of claim 10 , wherein the enzyme composition further comprises one or more enzymes selected from the group consisting of a cellulase, a polypeptide having cellulolytic enhancing activity, a hemicellulase, an expansin, an esterase, a laccase, a ligninolytic enzyme, a pectinase, a peroxidase, a protease, and a swollenin.

24. The method of claim 12 , wherein the enzyme composition further comprises one or more enzymes selected from the group consisting of a cellulase, a polypeptide having cellulolytic enhancing activity, a hemicellulase, an expansin, an esterase, a laccase, a ligninolytic enzyme, a pectinase, a peroxidase, a protease, and a swollenin.

25. The method of claim 13 , wherein the enzyme composition further comprises one or more enzymes selected from the group consisting of a cellulase, a polypeptide having cellulolytic enhancing activity, a hemicellulase, an expansin, an esterase, a laccase, a ligninolytic enzyme, a pectinase, a peroxidase, a protease, and a swollenin.

26. The variant of claim 1 , wherein the variant has at least 98% sequence identity to the mature polypeptide of SEQ ID NO: 2.

27. The variant of claim 1 , wherein the variant has at least 99% sequence identity to the mature polypeptide of SEQ ID NO: 2.