Characterization and pulp refining activity of a Paenibacillus campinasensis cellulase expressed in Escherichia coli.
The Cel-BL11 gene from Paenibacillus campinasensis BL11 was cloned and expressed in Escherichia coli as a His-tag fusion protein. Zymographic analysis of the recombinant protein revealed cellulase activity corresponding to a protein with a 38-kDa molecular weight. The optimum temperature and pH for purified cellulase were 60 °C and pH 7.0, respectively. The enzyme retained more than 80% activity after 8h at 60 °C at pH 6 and 7. The cellulase has a Km of 11.25 mg/ml and a Vmax of 1250 μmol/min/mg with carboxylmethyl cellulose (CMC). Then enzyme was active on Avicel, swollen Avicel, CMC, barley β-glucan, laminarin in the presence of 100 mM acetate buffer. It was inhibited by Hg²⁺, Cu²⁺ and Zn²⁺. Significant kraft pulp refining energy saving, 10%, was exhibited by the pretreatment of this cellulase applied at 2 IU per gram of oven-dried pulp. Broad pH and temperature stability render this cellulase a convenient applicability toward current mainstream biomass conversion and other industrial processes.
Ko
Chun-Han
CH
School of Forestry and Resource Conservation, National Taiwan University, Taipei 10617, Taiwan, ROC. chunhank@ntu.edu.tw
Tsai
Chung-Hung
CH
Lin
Po-Heng
PH
Chang
Ko-Cheng
KC
Tu
Jenn
J
Wang
Ya-Nang
YN
Yang
Chien-Ying
CY
D001483:Base Sequence; D002475:Cellobiose / Q000378:metabolism; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D056507:Paenibacillus / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature
D017931:DNA Primers; D011994:Recombinant Proteins; D002475:Cellobiose; D002480:Cellulase