Cellulase-free endo-xylanase enzyme of use in pulp delignification
AssigneeInstitut Armand Frappier
InventorsRoger L. Bernier, Dieter Kluepfel, Rolf Morosoli, Francois Shareck
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Abstract
A method of treating lignocellulosic material with a cellulase-free endo-xylanase for delignification, brightening and viscosity improvement. The endo-xylanase is obtained by the overexpression of the xylanase gene using a cellulase-negative recombinant microorganism of the genus Streptomyces. The recombinant microorganism is produced in a homologous cloning system in which the xylanase gene is inserted into a vector plasmid to provide the hybrid plasmid that is introduced into a host cellulase-negative mutant strain and said xylanase gene, said vector plasmid and said host mutant strain are obtained from microorganisms of the genus Streptomyces.
Claims27
A method of hydrolyzing the .beta.-1,4-D-xylosidic linkage within a lignocellulosic material having xylanase hydrolyzable .beta.-1,4-D-xylosidic linkages, said method comprising subjecting said material to said hydrolysis by a substantially cellulase-free xylanase obtained from the recombinant microorganism produced by the introduction of a hybrid plasmid into a host microorganism mutant strain of the strain Streptomyces, lividans said strain characterized by it having cellulase-negative activity, said hybrid plasmid being constructed by the insertion of the xylanase (xln) gene obtained from a xylanase (xln) gene-containing microorganism of the genus Streptomyces into a vector plasmid obtained from a microorganism of the genus Streptomyces.
A method of bleaching and/or delignification of a lignocellulosic material having xylanase hydrolyzable, B-1,4-D-xylosidic linkages, said method comprising subjecting said material to said hydrolysis by a substantially cellulase-free xylanase obtained from the recombinant microorganism produced by the introduction of a hybrid plasmid into a host microorganism mutant strain Streptomyces lividans, said strain characterized by it having cellulase-negative activity, said hybrid plasmid being constructed by the insertion of the xylanase (xln) gene obtained from a xylanase (xln) gene-containing microorganism of the strain Streptomyces lividans into a vector plasmid obtained from a microorganism of the strain Streptomyces lividans.
Dependencies are inferred from the claim text.