title: Precipitation of Trichoderma reesei commercial cellulase preparations under standard enzymatic hydrolysis conditions for lignocelluloses.
abstract: Comparative studies between commercial Trichoderma reesei cellulase preparations show that, depending on the preparation and loading, total protein precipitation can be as high as 30 % under standard hydrolysis conditions used for lignocellulosic materials. ATR-IR and SDS-PAGE data verify precipitates are protein-based and contain key cell wall hydrolyzing enzymes. Precipitation increased considerably with incubation temperature; roughly 50-150 % increase from 40 to 50 °C and 800 % greater at 60 °C. All of the reported protein losses translated into significant, and often drastic, losses in activity on related 4-nitrophenyl substrates. In addition, supplementation with the non-ionic surfactant PEG 6,000 decreased precipitation up to 80 % in 24 h precipitation levels. Protein precipitation is potentially substantial during enzymatic hydrolysis of lignocelluloses and should be accounted for during lignocellulose conversion process design, particularly when enzyme recycling is considered.
authors.affiliation: Faculty of Science, University of Copenhagen, Rolighedsvej 23, 1958, Frederiksberg C, Denmark. pchyle@life.ku.dk
authors.forename: Piotr
authors.initials: P
authors.lastname: Chylenski
authors.forename: Claus
authors.initials: C
authors.lastname: Felby
authors.forename: Mai
authors.initials: M
authors.lastname: Østergaard Haven
authors.forename: Miguel
authors.initials: M
authors.lastname: Gama
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Selig
mesh_terms: D056804:Biofuels; D002480:Cellulase / Q000737:chemistry / Q000302:isolation & purification*; D011232:Chemical Precipitation; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006358:Hot Temperature; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014242:Trichoderma / Q000201:enzymology* / Q000378:metabolism
chemical_list: D056804:Biofuels; D005656:Fungal Proteins; C036909:lignocellulose; D008031:Lignin; D002480:Cellulase