Enzymatic debranching is a key determinant of the xylan-degrading activity of family AA9 lytic polysaccharide monooxygenases
Journal article, 2023

Background:
Previous 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.
Results:
Using 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. Conclusions:
Our 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.

Cellulose

LPMO

Glucuronidase

Arabinofuranosidase

Lignocellulose

Lignocellulolytic cocktail

Lytic polysaccharide monooxygenase

Plant cell wall

Xylan

Author

Monika Tõlgo

Chalmers, Life Sciences, Industrial Biotechnology

Wallenberg Wood Science Center (WWSC)

Olav A. Hegnar

Norwegian University of Life Sciences

Johan Larsbrink

Chalmers, Life Sciences, Industrial Biotechnology

Wallenberg Wood Science Center (WWSC)

francisco Vilaplana

Royal Institute of Technology (KTH)

Wallenberg Wood Science Center (WWSC)

V. Eijsink

Norwegian University of Life Sciences

Lisbeth Olsson

Wallenberg Wood Science Center (WWSC)

Chalmers, Life Sciences, Industrial Biotechnology

Biotechnology for Biofuels and Bioproducts

27313654 (eISSN)

Vol. 16 1 2

Driving Forces

Sustainable development

Subject Categories

Industrial Biotechnology

Biocatalysis and Enzyme Technology

Organic Chemistry

Roots

Basic sciences

Infrastructure

Chemical Imaging Infrastructure

DOI

10.1186/s13068-022-02255-2

PubMed

36604763

More information

Latest update

1/3/2024 9