A novel cold-adapted cellulase complex from Eisenia foetida: characterization of a multienzyme complex with carboxymethylcellulase, beta-glucosidase, beta-1,3 glucanase, and beta-xylosidase

Abstract

Clostridium sp. and some bacterial cellulases exist as an enzyme complex with cellulolytic, and hemicellulolytic enzymes, so called "cellulosome". In this article, we report that EF-CMCase25 occurs as a complex with beta-glucosidase, beta-1,3 glucanase, and beta-xylosidase. The multienzyme complex had a molecular mass of 150 kDa on gel filtration under non-reducing condition. After the gel filtration, the enzyme complex was purified to homogeneous state on BN-PAGE. The SDS-PAGE demonstrated that the purified protein is a complex with at least one CMCase (25 kDa), one beta-glucosidase (32 kDa), and one beta-1,3 glucanase (40 kDa) components. The CMCase activity in the purified enzyme complex at 15 degrees C was 44% of that obtained at the optimal temperature. The optimum pH of the EF-CMCase25 in the purified enzyme complex was pH 5.0 and stable at pH 7.0-9.0.