title: Clostridium thermocellum releases coumaric acid during degradation of untreated grasses by the action of an unknown enzyme.
abstract: Clostridium thermocellum is an anaerobic thermophile with the ability to digest lignocellulosic biomass that has not been pretreated with high temperatures. Thermophilic anaerobes have previously been shown to more readily degrade grasses than wood. Part of the explanation for this may be the presence of relatively large amounts of coumaric acid in grasses, with linkages to both hemicellulose and lignin. We found that C. thermocellum and cell-free cellulase preparations both release coumaric acid from bagasse and switchgrass. Cellulase preparations from a mutant strain lacking the scaffoldin cipA still showed activity, though diminished. Deletion of all three proteins in C. thermocellum with ferulic acid esterase domains, either singly or in combination, did not eliminate the activity. Further work will be needed to identify the novel enzyme(s) responsible for the release of coumaric acid from grasses and to determine whether these enzymes are important factors of microbial biomass degradation.
authors.affiliation: Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA. chrisherringfish@gmail.com.|Mascoma Corporation, 67 Etna Road, Lebanon, NH, 03766, USA. chrisherringfish@gmail.com.|Enchi Corporation, 610 Lincoln Street, Waltham, MA, 02451, USA. chrisherringfish@gmail.com.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Herring
authors.affiliation: Mascoma Corporation, 67 Etna Road, Lebanon, NH, 03766, USA.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Thorne
authors.affiliation: Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH, 03755, USA.|Mascoma Corporation, 67 Etna Road, Lebanon, NH, 03766, USA.|Enchi Corporation, 610 Lincoln Street, Waltham, MA, 02451, USA.
authors.forename: Lee R
authors.initials: LR
authors.lastname: Lynd
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D002482:Cellulose / Q000378:metabolism; D048013:Acetivibrio thermocellus / Q000201:enzymology* / Q000378:metabolism*; D003373:Coumaric Acids / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism*; D008897:Panicum / Q000378:metabolism* / Q000382:microbiology*
chemical_list: D003373:Coumaric Acids; D004798:Enzymes; D002482:Cellulose; C027433:bagasse
keywords: Analytical chemistry; Cellulolytic microorganisms; Cellulosic ethanol; Coumaric acid esterase