title: Catalase improves saccharification of lignocellulose by reducing lytic polysaccharide monooxygenase-associated enzyme inactivation.
abstract: OBJECTIVE
  Efficient enzymatic saccharification of plant cell wall material is key to industrial processing of agricultural and forestry waste such as straw and wood chips into fuels and chemicals.
  
  
  RESULTS
  Saccharification assays were performed on steam-pretreated wheat straw under ambient and O2-deprived environments and in the absence and presence of a lytic polysaccharide monooxygenase (LPMO) and catalase. A kinetic model was used to calculate catalytic rate and first-order inactivation rate constants of the cellulases from reaction progress curves. The addition of a LPMO significantly (P < 0.01, Student's T test) enhanced the rate of glucose release from 2.8 to 6.9 h(-1) under ambient O2 conditions. However, this also significantly (P < 0.01, Student's T test) increased the rate of inactivation of the enzyme mixture, thereby reducing the performance half-life from 65 to 35 h. Decreasing O2 levels or, strikingly, the addition of catalase significantly reduced (P < 0.01, Student's T test) enzyme inactivation and, as a consequence, higher efficiency of the cellulolytic enzyme cocktail was achieved.
  
  
  CONCLUSIONS
  Oxidative inactivation of commercial cellulase mixtures is a significant factor influencing the overall saccharification efficiency and the addition of catalase can be used to protect these mixtures from inactivation.
authors.affiliation: Biomass Enzyme Discovery, Novozymes Inc., 1445 Drew Ave, Davis, CA, 95618, USA. bsco@novozymes.com.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Scott
authors.affiliation: Bioenergy Asia, Novozymes (China) Investment Co. Ltd., 14 Xinxi Road, Shangdi Zone, Haidian District, Beijing, 100085, China. hohu@novozymes.com.
authors.forename: Hong Zhi
authors.initials: HZ
authors.lastname: Huang
authors.affiliation: Biomass Application Discovery, Novozymes North America, 77 Perry's Chapel Church Road, Franklinton, NC, 27525, USA. jfri@novozymes.com.
authors.forename: Jesper
authors.initials: J
authors.lastname: Frickman
authors.affiliation: Biofuels Technology, Novozymes A/S, Krogshøjvej 36, 2880, Bagsværd, Denmark. ruhv@novozymes.com.
authors.forename: Rune
authors.initials: R
authors.lastname: Halvorsen
authors.affiliation: Biofuels Technology, Novozymes A/S, Krogshøjvej 36, 2880, Bagsværd, Denmark. skatja@chalmers.se.|Division of Industrial Biotechnology, Chalmers University of Technology, Kemivägen 10, 412 96, Göteborg, Sweden. skatja@chalmers.se.
authors.forename: Katja S
authors.initials: KS
authors.lastname: Johansen
mesh_terms: D002374:Catalase / Q000378:metabolism*; D044602:Cellulases / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010084:Oxidation-Reduction; D018547:Plant Stems / Q000378:metabolism; D014908:Triticum / Q000378:metabolism
chemical_list: C036909:lignocellulose; D008031:Lignin; D006899:Mixed Function Oxygenases; D002374:Catalase; D044602:Cellulases; D005947:Glucose
keywords: Catalase; Cellulase; Fenton chemistry; Kinetic modelling; Lytic polysaccharide monooxygenase; Pretreated wheat straw; Reactive oxygen species