title: High-temperature enzymatic breakdown of cellulose.
abstract: Cellulose is an abundant and renewable biopolymer that can be used for biofuel generation; however, structural entrapment with other cell wall components hinders enzyme-substrate interactions, a key bottleneck for ethanol production. Biomass is routinely subjected to treatments that facilitate cellulase-cellulose contacts. Cellulases and glucosidases act by hydrolyzing glycosidic bonds of linear glucose β-1,4-linked polymers, producing glucose. Here we describe eight high-temperature-operating cellulases (TCel enzymes) identified from a survey of thermobacterial and archaeal genomes. Three TCel enzymes preferentially hydrolyzed soluble cellulose, while two preferred insoluble cellulose such as cotton linters and filter paper. TCel enzymes had temperature optima ranging from 85°C to 102°C. TCel enzymes were stable, retaining 80% of initial activity after 120 h at 85°C. Two modes of cellulose breakdown, i.e., with endo- and exo-acting glucanases, were detected, and with two-enzyme combinations at 85°C, synergistic cellulase activity was observed for some enzyme combinations.
authors.affiliation: Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Wang
authors.forename: Fabio
authors.initials: F
authors.lastname: Squina
authors.forename: Fernando
authors.initials: F
authors.lastname: Segato
authors.forename: Andrew
authors.initials: A
authors.lastname: Mort
authors.forename: David
authors.initials: D
authors.lastname: Lee
authors.forename: Kirk
authors.initials: K
authors.lastname: Pappan
authors.forename: Rolf
authors.initials: R
authors.lastname: Prade
mesh_terms: D001105:Archaea / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D044602:Cellulases / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism; D005959:Glucosidases / Q000378:metabolism*; D006358:Hot Temperature; D006868:Hydrolysis
chemical_list: D000431:Ethanol; D002482:Cellulose; D044602:Cellulases; D005959:Glucosidases