CenC, a multi-domain thermo-stable GH9 processive endoglucanase from Clostridium thermocellum: Cloning, characterization and saccharification studies

7^th International Conference and Expo on Metabolomics

November 14-16, 2016 Orlando, Florida, USA

Ikram Ul Haq, Fatima Akram and Ali Nawaz

Government College University, Pakistan

Scientific Tracks Abstracts: Metabolomics

Abstract :

The growing demand of bioenergy has led to the emphasis on novel cellulases to improve efficiency of biodegradation process of plant biomass. Therefore, a thermo-stable cellulolytic gene (CenC) with 3,675 bp was cloned from Clostridium thermocellum and over-expressed in Escherichia coli strain BL21 Codon Plus. 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 up to 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. It efficiently hydrolyzed carboxy-methyl cellulose (30 U/mg), �²-glucan barley (94 U/mg); also showed activity towards p-nitro-phenyl-�²-D-cellobioside (18 U/mg), birch wood 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 thermo-stability, high catalytic efficiency and independence of inhibitors make CenC enzyme an appropriate candidate for industrial applications and cost-effective saccharification process.

Biography :

Ikram Ul Haq has completed his Post-doctorate from Cornell University, New York, USA and PhD in Industrial Microbiology from University of the Punjab, Lahore, Pakistan. He has been the Dean, Faculty of Science and Technology and Founding Director of Institute of Industrial Biotechnology, Government College University, Pakistan. He has successfully completed 11 projects sponsored by Pakistan Science Foundation, Pakistan Atomic Energy Commission, HEC, GCU & Ministry of Science and Technology while four projects are in process sponsored by MoST, PSF and Pakistan Academy of Sciences. He has published more than 300 papers in journals of international repute and has been serving as an Editorial Board Member of reputed journals.

Email: ikmhaq@yahoo.com