Journal of Microbiology and Biotechnology 2010-12-01

Purification and characterization of a thermostable cellobiohydrolase from Fomitopsis pinicola.

Keum Shin, Yoon Hee Kim, Marimuthu Jeya, Jung-Kul Lee, Yeong-Suk Kim

Index: J. Microbiol. Biotechnol. 20(12) , 1681-8, (2010)

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Abstract

A screening for cellobiohydrolase (CBH) activity was performed and Fomitopsis pinicola KMJ812 was selected for further characterization as it produced a high level of CBH activity. An extracellular CBH was purified to homogeneity by sequential chromatography of F. pinicola culture supernatants. The molecular mass of the F. pinicola CBH was determined to be 64 kDa by SDS-PAGE and by size-exclusion chromatography, indicating that the enzyme is a monomer. The F. pinicola CBH showed a t1/2 value of 42 h at 70 degrees C and catalytic efficiency of 15.8 mM-1 S-1 (kcat/ Km) for p-nitrophenyl-beta-D-cellobioside, one of the highest levels seen for CBH-producing microorganisms. Its internal amino acid sequences showed a significant homology with hydrolases from glycoside hydrolase family 7. Although CBHs have been purified and characterized from other sources, the F. pinicola CBH is distinguished from other CBHs by its high catalytic efficiency and thermostability.