The effect of ball milling on birch, pine, reed, walnut shell enzymatic hydrolysis recalcitrance and the structure of the isolated residual enzyme lignin

The Effect of Ball Milling Time on the Isolation of Lignin in the Cell Wall of Different Biomass

“…In the side-chain ( δ C / δ H 90–50/6.0–2.5) spectra, the substructures of ß -O-4 (A), ß -β (B), and ß -5 (C) in all MWL samples can be clearly observed by identifying their corresponding C–H correlation signals ( Jiang et al, 2017b ; Huang et al, 2020 ; Wang R. et al, 2021 ; Wang Z. et al, 2021 ). In addition, the lignin units of syringyl units (S), guaiacyl units (G), or p-hydroxyphenyl units (H) can also be observed in the aromatic region ( δ C / δ H 135–100/8.5–5.5) spectra of MWL samples with some differences ( Dong et al, 2020 ; Wang R. et al, 2021 ).…”

Mechanical pretreatment of lignocellulosic biomass toward enzymatic/fermentative valorization

“…Regarding the composition of the grinding material, most of the authors use zirconia ( Ji et al., 2018a ; Wang et al., 2021 ; Yu et al., 2019 ); however, steel ( Wu et al., 2021 ), agate ( Yang et al., 2022 ), aluminum oxide ( Kobayashi et al., 2021 ) and others ( Rajaonarivony et al., 2021 ), can be used. Over the last years, ball milling has been extensively used as size reduction pretreatment for biomass processing, not only because it is easy to perform but also because it can be used with chemicals (mechanochemical) to increase the efficiency of posterior treatments.…”

“…Two Cycles ( Wang et al., 2021 ) Pine 450 rpm, 6 h Min enzyme load (0.5 mL enzyme/g Biomass), <10% impurities. Two Cycles ( Wang et al., 2021 ) Reed 450 rpm, 6 h Min enzyme load (0.5 mL enzyme/g Biomass), <10% impurities. Three Cycles ( Wang et al., 2021 ) Walnut shell 450 rpm, 6h Min enzyme load (0.5 mL enzyme/g Biomass), <10% impurities.…”

“…Two Cycles ( Wang et al., 2021 ) Reed 450 rpm, 6 h Min enzyme load (0.5 mL enzyme/g Biomass), <10% impurities. Three Cycles ( Wang et al., 2021 ) Walnut shell 450 rpm, 6h Min enzyme load (0.5 mL enzyme/g Biomass), <10% impurities. Three Cycles ( Wang et al., 2021 ) Corn stover B500 rpm, 1-3 h Ball milling reduced the recalcitrant nature of LCB Optimal conditions lead to 69.65% xylo-oligosaccharides ( Zhang et al, 2021 ) Wheat straw 1, 2, 3, and 4 h, 450 rpm CrI a reduced from 46% to 7.6%, Glucose yield increased up to 99.4% (delignification 79.2%) ( Liu et al, 2022 ) Aspen Enzymatic digestion assisted Reduced enzymatic hydrolysis time from 72 h to 24 h and buffer solution, 84.7% glucose yield (24 h) ( Wu et al., 2021 ) Cellulose + chitin Enzymatic digestion assisted Enzymatic digestion is boosted by mechanical forces rather than local heat ( Kobayashi et al., 2021 ) Enset fibers 15, 30, 60, 90, and 120 min, 200, 350, and 500 rpm Dry chemo-chemical treatments increased glucose yield to a max of 621.3 g Glucose/Kg raw material in 90 min ( Sitotaw et al., 2022 ) Sugarcane bagasse + Pennisetum 2 h, 400 rpm (Assisted with NaOH solutions) Bagasse max reducing sugar yield 40.75%, 4% NaOH, hydrothermal 100°C 40 min Pennisetum max reducing sugars 55.74%, 4% NaOH, hydrothermal 80°C 60 min ( Huang et al, 2019 ) Soy bean meal 400 rpm and 2, 5, 8, 10, and 20 min Best result at 5 min milling time, 34.1 times more sugars than untreated soybean and 2.5 times more sugar than commercially used soybean meal ( Navarro-Mtz et al., 2019 ) Corn stover 10, 20, 30, 60, and 120 min, 20°C Crystallinity reduced from 46.52 to 5.04 (120 min) Ball milling allowed enzymatic digestion at high solids load, max monomeric sugar concentration (120 min, 30% solids load, and 10 FPU) ( …”

Solid-State Nuclear Magnetic Resonance as a Tool to Probe the Impact of Mechanical Preprocessing on the Structure and Arrangement of Plant Cell Wall Polymers

“…An overview of this process is provided in Figure 1A . However, milling leading to recalcitrance is frequently reported during lignocellulosic biomass conversion efforts, impeding the efficiency of subsequent processing and separation steps ( Tolbert et al, 2014 ; Li et al, 2016 ; Wang et al, 2021 ). Milling-induced recalcitrance could be due to the production of reactive lignin species ( Zhao et al, 2016 ) promoting aberrant hemicellulose-lignin crosslinks ( Terrett and Dupree, 2019 ) as the lignin recondenses ( Li et al, 2016 ; Kang et al, 2019 ).…”