Research Article
Dal Rye Kim, Hee Kyung Lim
Abstract
The 1,4-β-D-glucan glucohydrolase gene (Ggh) which was isolated from Paenibacillus sp. strain HPL-001 (KCTC11365BP) has been cloned and expressed in Escherichia coli, and efficiently purified using affinity column chromatography. Recombinant 1,4-β-Dglucan glucohydrolase (719aa, NCBI accession number KJ573391) was highly active at 40°C in pH 6.0 without significant changes to most salts tested, and exhibited Km 0.893 mg/mL Vmax 33.33 U/mg on pNPG, respectively. All soluble cellooligomers (e.g., cellobiose, cellotriose, cellotetraose, cellopentaose, and cellohexaose) had been virtually hydrolyzed to glucose by this enzyme. When compared with the commercialized-enzymes, the hydrolytic pattern to all substrates was almost same to the Celluclast 1.5L (Novozyme) with about 1/3 strength, however hydrolytic pattern of Glucosidase (Lucigen) and Almonds (Sigma) was significantly decreased with substrates increasing number of glucose polymer from cellotriose to cellohexaose. About 90% of the initial enzyme activity was maintained even after 10 consecutive recycle by the 11-carbon bridge and aldehyde-functionalized MCF-immobilization. 3-D structure of this enzyme has the ligand of cellobiose and cellulose binding in the center of niche according to the sequence information.