Insights into the action of phylogenetically diverse microbial expansins on the structure of cellulose microfibrils
Beskrivning
Abstract Background Microbial expansins (EXLXs) are non-lytic proteins homologous to plant expansins involved in plant cell wall formation. Due to their non-lytic cell wall loosening properties and potential to disaggregate cellulosic structures, there is considerable interest in exploring the ability of microbial expansins (EXLX) to assist the processing of cellulosic biomass for broader biotechnological applications. Herein, EXLXs with different modular structure and from diverse phylogenetic origin were compared in terms of ability to bind cellulosic, xylosic, and chitinous substrates, to structurally modify cellulosic fibrils, and to boost enzymatic deconstruction of hardwood pulp. Results Five heterogeneously produced EXLXs (Clavibacter michiganensis; CmiEXLX2, Dickeya aquatica; DaqEXLX1, Xanthomonas sacchari; XsaEXLX1, Nothophytophthora sp.; NspEXLX1 and Phytophthora cactorum; PcaEXLX1) were shown to bind xylan and hardwood pulp at pH 5.5 and CmiEXLX2 (harboring a family-2 carbohydrate-binding module) also bound well to crystalline cellulose. Small-angle X-ray scattering revealed a 20–25% increase in interfibrillar distance between neighboring cellulose microfibrils following treatment with CmiEXLX2, DaqEXLX1, or NspEXLX1. Correspondingly, combining xylanase with CmiEXLX2 and DaqEXLX1 increased product yield from hardwood pulp by ~ 25%, while supplementing the TrAA9A LPMO from Trichoderma reesei with CmiEXLX2, DaqEXLX1, and NspEXLX1 increased total product yield by over 35%. Conclusion This direct comparison of diverse EXLXs revealed consistent impacts on interfibrillar spacing of cellulose microfibers and performance of carbohydrate-active enzymes predicted to act on fiber surfaces. These findings uncover new possibilities to employ EXLXs in the creation of value-added materials from cellulosic biomass.
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2024
Typ av data
Upphovspersoner
Department of Bioproducts and Biosystems
Anu Koivula - Upphovsperson
Garry W. Buchko - Upphovsperson
Janak Sapkota - Upphovsperson
Kaisa Marjamaa - Upphovsperson
Majid Haddad Momeni - Upphovsperson
Natalia Maiorova - Upphovsperson
Rosaliina Turunen - Upphovsperson
Salla Hiltunen - Upphovsperson
Vilma Jäämuru - Upphovsperson
University of Toronto - Medarbetare
VTT Technical Research Centre of Finland Ltd. - Medarbetare
Washington State University - Medarbetare
figshare - Utgivare
Projekt
Övriga uppgifter
Vetenskapsområden
Biokemi, cell- och molekylärbiologi
Språk
Öppen tillgång
Öppet