Novel laccase from ganoderma lucidum capable of enhancing enzymatic degradation of lignocellulolytic biomass

Abstract

The invention addresses the need for enzymes that can enhance the yield of fermentable sugar from the hydrolysis of lignocellulose biomass, for example sugar cane bagasse, barley straw and wheat straw, such that the use of this biomass can become economically viable. The invention provides methods for the hydrolysis of biomass using a laccase derived from Ganoderma lucidum . Further, the invention provides an enzyme composition comprising a laccase derived from Ganoderma lucidum which may be combined with one or more cellulases, and for its use in enhancing lignocellulose biomass hydrolysis.

1 .- 8 . (canceled) 
     
     
         9 . An enzyme composition suitable for enhancing enzymatic hydrolysis of lignocellulose biomass, comprising a fungal laccase, wherein the laccase is a polypeptide having at least 85% amino acid sequence identity to SEQ ID NO: 5. 
     
     
         10 . The enzyme composition according to  claim 9 , further comprising one or more cellulose hydrolysing enzyme selected from among an endo-β-1,4-glucanase (EC 3.2.1.4), exoglucanase (EC 3.2.1.91) and β-glucosidase (EC 3.2.1.21). 
     
     
         11 . The enzyme composition according to  claim 9 , wherein the composition is formulated as any one of a dry powder, a dry tablet or a liquid. 
     
     
         12 . The enzyme composition according to  claim 9 , wherein the polypeptide additionally comprises a heterologous carboxy-terminal peptide and wherein the peptide has selective substrate binding affinity suitable for purification of the polypeptide. 
     
     
         13 . The enzyme composition according to  claim 9 , wherein the amino acid sequence of the fungal laccase (EC 1.10.3.2) is at least 499 amino acid residues in length and has at least 90% amino acid sequence identity to SEQ ID NO: 5. 
     
     
         14 . The enzyme composition according to  claim 9 , wherein the fungal laccase is a recombinant polypeptide obtained by recombinant expression in a host cell selected from any one of  Aspergillus niger, Aspergillus tubigensis, Aspergillus awamori, Trichoderma reesei, Penicillium funiculosum, Hansenula polymorpha Bacillus subtilis, Bacillus licheniformis , and  Escherichia coli.    
     
     
         15 . Use of an enzyme composition according to  claim 9  for enhancing cellulase-mediated hydrolysis of lignocellulose biomass. 
     
     
         16 . The enzyme composition according to  claim 9 , wherein the laccase is a polypeptide having at least 95% amino acid sequence identity to SEQ ID NO: 5. 
     
     
         17 . The enzyme composition according to  claim 9 , wherein the laccase is a polypeptide having at least 99% amino acid sequence identity to SEQ ID NO: 5.