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Why does GH10 xylanase have better performance than GH11 xylanase for the deconstruction of pretreated biomass?

Hu, Jinguang, Saddler, Jack N.
Biomass and bioenergy 2018 v.110 pp. 13-16
biocatalysts, biomass, biorefining, economic sustainability, endo-1,4-beta-glucanase, endo-1,4-beta-xylanase, engineering, glycosides, hydrolysis, laccase, moieties, thermal stability, xylan
One approach to improve biomass deconstruction is to formulate a more efficient cellulase cocktail by adding “accessory enzymes” (e.g. xylanase/LPMO/laccases). Among different xylanases, glycoside hydrolase family 10 endo-xylanase (GH10EX) shows better performance than family 11 endo-xylanase (GH11EX) even though GH11EX has better kinetic activity on various xylan substrates. To better understand this phenomenon, the xylan accessibility of GH10/11 xylanases was assessed on various “model” and realistic cellulosic substrates and their thermostability was also compared during time course of hydrolysis. It showed that GH10EX had higher accessibility towards the xylan backbone within pretreated biomass, especially for these with higher acetyl group content. Acetyl group removal could greatly intensify the synergistic cooperation between GH11EX and cellulases. Additionally, the higher thermostability of GH10EX appeared to be another reason for its outstanding potential during biomass decomposition. This work provides further insights for engineering better biocatalysts to enhance the economic viability of enzyme based biorefinery.