Facile, room-temperature pre-treatment of rice husks with tetrabutylphosphonium hydroxide: Enhanced enzymatic and acid hydrolysis yields

A Cation Study on Rice Husk Biomass Pretreatment with Aqueous Hydroxides: Cellulose Solubility Does Not Correlate with Improved Enzymatic Hydrolysis

“…14 ± 1 wt% silica, and silica solubility Silica dissolution likely proceeds by chemical reaction exclusively with the hydroxide anion, followed by solubilisation of the [Si(OH) 4 ]anion. 5,41 These results demonstrate that silica dissolution and solvation is essentially independent of the nature of the cation (within uncertainty), all systems dissolving ca. 14 ± 1 wt% amorphous silica gel.…”

“…Hydroxide solutions are also known solvents for silica 11 and have been found to be effective in disrupting the silica layer surrounding rice husks. [4][5] Alkali metal hydroxides such as sodium hydroxide (Na [OH]) are widely employed for the swelling of cellulose. [12][13][14] Solutions of Na [OH] can dissolve cellulose, but only below 4°C.…”

“…33 Limited comparisons of Na[OH] and K [OH] have also been performed on rice-based agricultural waste; pre-treatment with K[OH] was more effective for downstream production of cellulase via fermentation, 34 whereas Na [OH] was more effective as judged by downstream sugar production by cellulase 35 (at room temperature) followed by acid or enzymatic hydrolysis has been investigated, and compared to straight acid treatment and rice husks pre-treated in refluxing K [OH]. 5 Pre-treatment of switchgrass with [N 4444 ][OH] (at 50°C) then 5 downstream enzymatic saccharification has also been reported. 36 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 6 undissolved after 24 hours of stirring, or the solution became too viscous to be stirred (e.g.…”

Total quantification and extraction of shikimic acid from star anise (llicium verum) using solid-state NMR and cellulose-dissolving aqueous hydroxide solutions

“…[58] Lignin and silica are also highly soluble in all of these media. [51] Therefore the solubility of star anise powder was investigated in a range of hydroxide systems with a fixed UV-Vis analysis (Figure 3(a)) demonstrated that methanol extracted only some UV absorbing substances, with a small peak present at ca. 265 nm; the absorbance increased from …”

Rapid and Complete Dissolution of Softwood Biomass in Tetra-n-butylphosphonium Hydroxide with Hydrogen Peroxide

“…It has been reported that 40% to 70% aq. [P4,4,4,4]OH solutions can readily dissolve cellulose (Abe et al 2012), some woody biomasses (Abe et al 2014), wheat (Hyväkkö et al 2014), and rice husks (Lau et al 2015) at low temperature. Furthermore, woody biomass can be almost completely dissolved in 60% [P4,4,4,4]OH with the addition of hydrogen peroxide (H2O2) as a dissolution accelerator (Abe et al 2015).…”