Cationic xylan

K—xyhui plus cyclodextrin F-containing cationic xylan <... 

Figure 7. AFM height image (left) and phase images (right) of a 40-layer cellulose LB film treated with an aqueous solution of the F-containing cationic xylan derivative. Note the spherical particles deposited on the image on the right side.

Cationic xylan improve the paper making properties of pulp (16), Xylan samples from beech wood (4-0-methyl glucurono xylan, GX) and com cobs (arabino-(4-0-methyl glucurono) xylan, AGX) were converted into TMAHP... 

The TMAHP-MGX isolated from cationized aspen sawdust was reported to be applicable as a beater additive it significantly increased the tear strength of bleached spruce organosolv pulp [3]. The TMAHP derivatives prepared from isolated xylans were shown to improve the paper-making properties and... 

Fig. 18 Reaction pathways for the introduction of cationic moieties into xylan...

Enzyme activity loss because of non-productive adsorption on lignin surface was identified as one of the important factors to decrease enzyme effectiveness, and the effect of surfactants and non-catalytic protein on the enzymatic hydrolysis has been extensively studied to increase the enzymatic hydrolysis of cellulose into fermentable sugars [7, 9 19]. The reported study showed that the non-ionic surfactant poly(oxyethylene)2o-sorbitan-monooleate (Tween 80) enhanced the enzymatic hydrolysis rate and extent of newspaper cellulose by 33 and 14%, respectively [20]. It was also found that 30% more FPU cellulase activity remained in solution, and about three times more recoverable FPU activity could be recycled with the presence of Tween 80. Tween 80 enhanced enzymatic hydrolysis yields for steam-exploded poplar wood by 20% in the simultaneous saccharification and fermentation (SSF) process [21]. Helle et al. [22] reported that hydrolysis yield increased by as much as a factor of 7, whereas enzyme adsorption on cellulose decreased because of the addition of Tween 80. With the presence of poly(oxyethylene)2o-sorbitan-monolaurate (Tween 20) and Tween 80, the conversions of cellulose and xylan in lime-pretreated com stover were increased by 42 and 40%, respectively [23]. Wu and Ju [24] showed that the addition of Tween 20 or Tween 80 to waste newsprint could increase cellulose conversion by about 50% with the saving of cellulase loading of 80%. With the addition of non-ionic, anionic, and cationic surfactants to the hydrolysis of cellulose (Avicel, tissue paper, and reclaimed paper), Ooshima et al. [25] subsequently found that Tween 20 was the most effective for the enhancement of cellulose conversion, and anionic surfactants did not have any effect on cellulose hydrolysis. With the addition of Tween 20 in the SSF process for... 

They developed evidence for complex formation between the xylans and some Group II cations, and in this Instance it seems quite unlikely that more than 2 hydroxyl groups per residue can be coordinated to the same metal ions. 

Strom G, Barla P, Stenins P (1985) The formation of polyelectrolyte complexes between pine xylan and cationic polymers. Colloids Surf 13 193-207... 

In the case of water-soluble O-acetylated xylans and glucomannans, an ammonium acetate solution with a pH of 7 was employed as eluent in connection with the SEC separation step (7). However, for dkali extracted xylans and glucomannans, a more alkaline (pH 13) sodium hydroxide/acetate eluent was required (3). In all cases pretreatment of the SEC fractions by passage through a cation-exchange resin prior to MALDI-MS analysis and/or the use of MALDI probes coated with a Nafion film (2), were necessary in order to minimize the disturbance by buffer ions during the MALDI analysis step. 

Based on the above results, it was clear dut more drastic changes in r lan structure were required to promote adsorption ( docking ). Hence cationic and F-containing xylan derivatives were examined given the strong hydrophobic effect seen for F-containing CTP derivatives. Cationically-... 

The amount of adsorbed xylan (heteropolysaccharide) is promoted by cationic functionality as well as by enhancing the anq)hiphilic character widi strongly hydrophobic (F-containing) substituents. 

The higher the molar mass of the mannan, the better was its stabilizing effect. Deacetylated GGMs, in turn, were poor stabilizers. A birch xylan was also an excellent stabilizer, while neutral and cationic starches were not very effective. However, in another similar study birch xylan was found to have only a minor stabilizing effect [52]. 

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