Endo β-1,4-mannanases (β-mannanases, EC 3.2.1.78), belonging to CAZy GH5 and GH26 families, catalyze the hydrolysis of structurally different mannans. In this study, the mannanase encoding gene of Aspergillus aculeatus VN was expressed in Aspergillus niger D15#26 using pAN 52-4 vector, under the control of P. gpdA promoter and T. trpC terminator. In order to improve the hydrolytic capacity of this GH5 on lignocellulosic substrate, the family 1 carbohydrate-binding module (CBM1) of Aspergillus niger cellobiohydrolase B was artificially fused at the C-terminal end of this enzyme with a natural linker. Both mannanase and mannanase-CBM genes were successfully expressed in A. niger D15#26, producing proteins with molecular masses of 54 and 79. kDa, respectively. The Michaelis-Menten constants, pH activity profiles and temperature optima of three enzymes (wild-type mannanase, recombinant mannanase and recombinant mannanase-CBM) were similar, but the fused mannanase-CBM enzyme was more thermostable. Cross-comparison of the three enzymes for softwood hydrolysis in association with Trichoderma reesei enzymatic cocktail showed that mannanase-CBM improved the glucose yield compared to wild-type and recombinant mannanases. © 2010 Elsevier B.V.

Pham T.A., Berrin J.G., Record E., To K.A., Sigoillot J.-C.

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Từ khóa : Aspergillus aculeatus; Aspergillus niger; CBM1; GH5; Mannanase; Carbohydrates; Catalysts; Enzymes; Gene encoding; Glucose; Softwoods; Hydrolysis; beta mannosidase; carbohydrate binding molecule 1; carbohydrate binding protein; cellulose 1,4 beta cellobiosidase; glucose; unclassified drug; article; Aspergillus; aspergillus aculeatus; Aspergillus niger; comparative study; controlled study; enzyme activity; fungal strain; fungus culture; gene control; gene expression; hydrolysis; Hypocrea jecorina; molecular cloning; nonhuman; nucleotide sequence; pH measurement; priority journal; promoter region; protein expression; protein purification; thermostability; vector control; Aspergillus; Aspergillus aculeatus; Aspergillus niger; Hypocrea jecorina