title: Recycling cellulases for cellulosic ethanol production at industrial relevant conditions: potential and temperature dependency at high solid processes.
abstract: Different versions of two commercial cellulases were tested for their recyclability of enzymatic activity at high dry matter processes (12% or 25% DM). Recyclability was assessed by measuring remaining enzyme activity in fermentation broth and the ability of enzymes to hydrolyse fresh, pretreated wheat straw. Industrial conditions were used to study the impact of hydrolysis temperature (40 or 50°C) and residence time on recyclability. Enzyme recycling at 12% DM indicated that hydrolysis at 50°C, though ideal for ethanol yield, should be kept short or carried out at lower temperature to preserve enzymatic activity. Best results for enzyme recycling at 25% DM was 59% and 41% of original enzyme load for a Celluclast:Novozyme188 mixture and a modern cellulase preparation, respectively. However, issues with stability of enzymes and their strong adsorption to residual solids still pose a challenge for applicable methods in enzyme recycling.
authors.affiliation: University of Copenhagen, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark. Electronic address: lindedam@life.ku.dk.
authors.forename: Jane
authors.initials: J
authors.lastname: Lindedam
authors.forename: Mai Østergaard
authors.initials: MØ
authors.lastname: Haven
authors.forename: Piotr
authors.initials: P
authors.lastname: Chylenski
authors.forename: Henning
authors.initials: H
authors.lastname: Jørgensen
authors.forename: Claus
authors.initials: C
authors.lastname: Felby
mesh_terms: D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism; D044602:Cellulases / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006868:Hydrolysis; D007221:Industry; D059027:Recycling; D013696:Temperature; D013997:Time Factors; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D000431:Ethanol; D002482:Cellulose; D044602:Cellulases; D001617:beta-Glucosidase; D043364:Endo-1,4-beta Xylanases
keywords: Biofuels; Cellulases; Enzyme recycling; Remaining activity; Thermostability