Monday, April 30, 2007 - 8:30 AM

More than one protein takes part in the separation of cellulose fibers during the enzymatic degradation of cellulose by Trichoderma reesei

Abdul Aala Najmus Saqib, Philip John Whitney, Claudio Avignone-Rossa, and Michael Bushell. School of Biomedical and Molecular Sciences, University of Surrey, Guildford, United Kingdom

Cellulases are important enzymes in many industrial processes such as production of biofuels from the cellulosic materials. They liberate glucose units from the polymer cellulose. Cellulose is mostly crystalline in nature. It is believed that the microorganisms which are adept at enzymatic degradation of cellulose break the barrier of crystallinity by separating the otherwise tightly packed cellulose fibrils (1). Understanding the exact mechanism of this step in the enzymatic hydrolysis of cellulose is still in its infancy. When elucidated, it could be used to enhance the enzymatic degradation of cellulose.

We have found out that more than one protein takes part in the cellulose fiber-separation process by the culture filtrate of the fungus Trichoderma reesei. The culture filtrate of T. reesei was fractionated by gel filtration, ion-exchange chromatography and hydrophobic interaction chromatography. SDS-PAGE was used to monitor the extent and nature of the purification. None of the partially purified peaks could breakdown the cellulose as shown by filter paper degradation assay, although their mixture could. The results were further confirmed by scanning electron microscopy and particle size analysis. This shows that the activity was the result of interaction of different components of the culture filtrate rather than the effect of a previously undetected component.

1. Saqib, A.A.N. and Whitney, P.J., (2006), Role of fragmentation activity in cellulose hydrolysis, International Biodegradation & Biodeterioration. 58: 180-185.