Enzymatic debranching is a key determinant of the xylan-degrading activity of family AA9 lytic polysaccharide monooxygenases

Biotechnology for Biofuels and Bioproducts

Research

Francisco Vilaplana¹  Monika Tõlgo²  Johan Larsbrink²  Lisbeth Olsson²  Olav A. Hegnar³  Vincent G. H. Eijsink³ 

[1] Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, 106 91, Stockholm, Sweden;Wallenberg Wood Science Centre, KTH Royal Institute of Technology, 100 44, Stockholm, Sweden;Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96, Gothenburg, Sweden;Wallenberg Wood Science Centre, Chalmers University of Technology, 412 96, Gothenburg, Sweden;Faculty of Chemistry, Biotechnology and Food Science, NMBU-Norwegian University of Life Sciences, 1433, Ås, Norway;

关键词: Lytic polysaccharide monooxygenase;    LPMO;    Arabinofuranosidase;    Glucuronidase;    Lignocellulolytic cocktail;    Plant cell wall;    Lignocellulose;    Cellulose;    Xylan;   

DOI  :  10.1186/s13068-022-02255-2

 received in 2022-09-13, accepted in 2022-12-26,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundPrevious studies have revealed that some Auxiliary Activity family 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) oxidize and degrade certain types of xylans when incubated with mixtures of xylan and cellulose. Here, we demonstrate that the xylanolytic activities of two xylan-active LPMOs, TtLPMO9E and TtLPMO9G from Thermothielavioides terrestris, strongly depend on the presence of xylan substitutions.ResultsUsing mixtures of phosphoric acid-swollen cellulose (PASC) and wheat arabinoxylan (WAX), we show that removal of arabinosyl substitutions with a GH62 arabinofuranosidase resulted in better adsorption of xylan to cellulose, and enabled LPMO-catalyzed cleavage of this xylan. Furthermore, experiments with mixtures of PASC and arabinoglucuronoxylan from spruce showed that debranching of xylan with the GH62 arabinofuranosidase and a GH115 glucuronidase promoted LPMO activity. Analyses of mixtures with PASC and (non-arabinosylated) beechwood glucuronoxylan showed that GH115 action promoted LPMO activity also on this xylan. Remarkably, when WAX was incubated with Avicel instead of PASC in the presence of the GH62, both xylan and cellulose degradation by the LPMO9 were impaired, showing that the formation of cellulose–xylan complexes and their susceptibility to LPMO action also depend on the properties of the cellulose. These debranching effects not only relate to modulation of the cellulose–xylan interaction, which influences the conformation and rigidity of the xylan, but likely also affect the LPMO–xylan interaction, because debranching changes the architecture of the xylan surface.ConclusionsOur results shed new light on xylanolytic LPMO9 activity and on the functional interplay and possible synergies between the members of complex lignocellulolytic enzyme cocktails. These findings will be relevant for the development of future lignocellulolytic cocktails and biomaterials.

【 授权许可】

CC BY   
© The Author(s) 2023

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