Journal of Fundamentals of Renewable Energy and Applications
Open Access
ISSN: 2090-4541
ISSN: 2090-4541
Ikram-ul-Haq
Government College University, Pakistan
Posters & Accepted Abstracts: J Fundam Renewable Energy Appl
The growing demands of bioenergy have led to the emphasis on novel cellulases to improve efficiency of biodegradation process of plant biomass. Therefore, a thermostable cellulolytic gene (CenC) with 3,675 bp was cloned from Clostridium thermocellum and over-expressed in Escherichia coli strain BL21 CodonPlus. It was attested that CenC belongs to glycoside hydrolase family 9 (GH9) with four binding domains, a processive endoglucanase. CenC was purified to homogeneity, producing a single band on SDS-PAGE corresponding to 137.11 kDa, by purification steps of heat treatment combined with ion-exchange chromatography. Purified enzyme displayed optimal activity at pH 6.0 and 70�?°C. CenC had a half-life of 24 min at 74�?°C, was stable upto 2 h at 60�?°C and over a pH range of 5.5-7.5. Enzyme showed high affinity towards various substrates and processively released cellobiose from cellulosic substrates confirmed by using HPLC technique. It efficiently hydrolyzed carboxymethyl cellulose (30 U/mg), �?²-glucan Barley (94 U/mg); also showed activity towards p-nitrophenyl-�?²-D-cellobioside (18 U/mg), birchwood xylan (19 U/mg), beechwood xylan (17.5 U/mg), avicel (9 U/mg), whatman filter paper (11 U/mg) and laminarin (3.3 U/mg). CenC exhibited Km, Vmax, Kcat, Vmax Km -1 and Kcat Km-1 of 7.14 mM, 52.4 �?¼mol mg-1min-1, 632.85 s-1, 7.34 min-1 and 88.63, respectively used CMC as substrate. Recombinant CenC saccharified pretreated wheat straw and bagasse to 5.12% and 7.31%, respectively at pH 7.0 and 45�?°C after 2 h incubation. Its thermostability, high catalytic efficiency and independence of inhibitors make CenC enzyme an appropriate candidate for industrial applications and cost-effective saccharification process.
Email: ikmhaq@yahoo.com