Isolation and modification of nano-scale cellulose from organosolv-treated birch through the synergistic activity of LPMO and endoglucanases

• Main Authors: Christakopoulos, P. (Author), Karnaouri, A. (Author), Liu, B. (Author), Mathew, A.P (Author), Matsakas, L. (Author), Muraleedharan, M.N (Author), Piatkova, M. (Author), Rova, U. (Author), Ruiz-Caldas, M.-X (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2021
• Subjects: Article; atomic force microscopy; Betula; Betula pendula; biomass; Biomass; birch; budding yeast; carboxylic acid; cellulase; Cellulase; cellulose; Cellulose; controlled study; enzyme specificity; enzymology; genetics; glucan synthase; hydrolysis; Hydrolysis; hydrophobic interaction chromatography; isolation and purification; Komagataella pastoris; laccase; Laccase; lignin; Lignin; lignocellulose; LPMO biocatalysis; lytic polysaccharide monooxygenase; metabolism; mixed function oxidase; Mixed Function Oxygenases; molecular cloning; Myceliophthora thermophila; nanocellulose; Nanocellulose; nanofiber; Nanofibers; nonhuman; organic solvent; organosolv; Phanerochaete; Post-treatment modification/functionalization; regioselectivity; Saccharomycetales; scanning electron microscopy; Sordariales; Substrate Specificity; suspension; thermogravimetry; thermostability; unclassified drug; unspecific monooxygenase; X ray photoemission spectroscopy; xylan 1,4 beta xylosidase; Xylosidases; zeta potential
• Online Access: View Fulltext in Publisher

 Nanocellulose isolation from lignocellulose is a tedious and expensive process with high energy and harsh chemical requirements, primarily due to the recalcitrance of the substrate, which otherwise would have been cost-effective due to its abundance. Replacing the chemical steps with biocatalytic processes offers opportunities to solve this bottleneck to a certain extent due to the enzymes substrate specificity and mild reaction chemistry. In this work, we demonstrate the isolation of sulphate-free nanocellulose from organosolv pretreated birch biomass using different glycosyl-hydrolases, along with accessory oxidative enzymes including a lytic polysaccharide monooxygenase (LPMO). The suggested process produced colloidal nanocellulose suspensions (ζ-potential −19.4 mV) with particles of 7–20 nm diameter, high carboxylate content and improved thermostability (To = 301 °C, Tmax = 337 °C). Nanocelluloses were subjected to post-modification using LPMOs of different regioselectivity. The sample from chemical route was the least favorable for LPMO to enhance the carboxylate content, while that from the C1-specific LPMO treatment showed the highest increase in carboxylate content. © 2021