Engineered bifunctional enzymes of endo-1,4-β-xylanase/endo-1,4-β-mannanase were constructed for synergistically hydrolyzing hemicellulose

Xylanase and mannanase were widely used in various application fields for degrading hemicellulose. The coordinated action of them could significantly improve hemicellulose hydrolysis. To enhance the synergistic action of xylanase and mannanase on hemicellulose, twelve chimeras of xylanase and mannanase were constructed and expressed in Pichia pastoris. The data presented that the types of peptide linker, the length of linker and the integration order of two enzymes had great effects on the properties of chimeras and synergistic efficiencies toward the hydrolysis of luffa cylindrica fiber. The chimera XE3M, with rigid a-helix-forming peptide A[EAAAK](3)A as linker and xylanase at the N-terminal, greatly improved the hydrolysis of luffa cylindrica fiber. It revealed that the synergistic action of xylanase and mannanase on hemicelluloses could be strengthened by constructing proper chimeras. And it would be useful for developing an economical process for hemicellulose hydrolysis. (C) 2013 Elsevier B.V. All rights reserved.