1Department of Biotechnology, Guwahati, 781039, Assam, India
2Center for Environment, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
3Department of Biotechnology and Environmental Sciences, Thapar University, Bhadson Road, Patiala, 140007, Punjab, India.
4CIISA-Faculdade de Medicina Veterinária, Pólo Universitário do Alto da Ajuda, Avenida da Universidade Técnica, 1300-477, Lisboa, Portugal.
*For Correspondence: arungoyl@iitg.ernet.in
The truncated cellulase derivative (CtLic26A-Cel5) from Clostridium thermocellum cloned earlier into an expression vector pET21a was over-expressed using Escherichia coli cells (Taylor et al. 2005). The recombinant cellulase derivative (CtLic26A-Cel5) was purified by immobilized metal ion affinity chromatography. The purified enzyme on SDS-PAGE showed a single homogeneous band of molecular mass of 64 kDa. The enzyme derivative CtLic26A-Cel5 showed catalytic activity with soluble substrates such as lichenan, β-glucan and carboxymethyl cellulose. It also hydrolyzed insoluble substrates such as acid swollen cellulose, avicel and steam exploded bagasse. The cellulase derivative CtLic26A-Cel5 gave an optimum temperature of 50°C and an optimum pH of 4.3 for maximum activity when assayed with carboxymethyl cellulase as a substrate. Analysis of the thermal stability of enzyme derivative (CtLic26A-Cel5) revealed that the enzyme is maximally stable at 50°C. The Mg2+, Ca2+, Ni2+ and Na+ ions enhanced significantly (1.8–2.3 fold), the enzyme activity of clostridial recombinant derivative.
Clostridium thermocellum, cellulase, cellulose, carboxymethyl cellulose, bagasse
