|Li, Xin Liang|
Submitted to: Applied Biochemistry and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2002
Publication Date: 4/1/2002
Citation: CHEN, H., LI, X., BLUM, D.L., XIMENES, E.A., LJUNGDAHL, L.G. CELF OF ORPINOMYCES PC-2 HAS AN INTRON AND ENCODES A CELLULASE (CELF) CONTAINING A CARBOHYDRATE-BINDING MODULE. JOURNAL OF APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY. 2003. V. 105-108. P. 775-785.
Interpretive Summary: Efficient conversion of agricultural biomass such as straw and corn stalks to fermentable sugars has been recognized as the major bottleneck for the economical production of biofuels and feedstock chemicals from the almost infinite renewable resources. There are three major constitutes, cellulose, hemicellulose, and lignin, commonly found in biomass. Biological degradation of the three constitutes requires many different enzymes to work together as a consortium. The most needed enzymes are those which tackle cellulose and hemicelluloses. Fungal microorganisms isolated from cattle have been demonstrated to be a source for the enzymes that are the most active at degrading these materials. However, these particular fungi are hard to grow, and their cellulose degrading enzymes, cellulases, have only recently been investigated. The present paper reports on a cellulase gene from one of these fungi, Orpinomyces PC-2. This cellulase differs from most other cellulases which make it more efficient in the degradation of natural, crystalline cellulose. Due to its high activity against cellulose, the enzyme will be one of the candidates evaluated for conversion of agricultural biomass to biofuels.
Technical Abstract: A cDNA, designated celF, encoding a cellulase (CelF) was isolated from the anaerobic fungus Orpinomyces PC-2. The open reading frame contains regions coding for a signal peptide, a carbohydrate binding module (CBM), linker, and a catalytic domain (CD). The CD was homologous to those of CelA and CelC of the same fungus and to that of the Neocallimastix patriciarum CELA, but CelF lacks a docking domain, characteristic for enzymes of cellulosomes. It is also homologous to the cellobiohydrolase IIs and endoglucanases of aerobic organisms. The gene has a 111-bp intron, located within the CBM-coding region. Some biochemical properties of the purified recombinant enzyme are described.