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Changes in Lignin and Polysaccharide Components in 13 Cultivars of Rice Straw following Dilute Acid Pretreatment as Studied by Solution-State 2D 1H-13C NMR.

Teramura H, Sasaki K, Oshima T, Aikawa S, Matsuda F, Okamoto M, Shirai T, Kawaguchi H, Ogino C, Yamasaki M, Kikuchi J, Kondo A - PLoS ONE (2015)

Bottom Line: In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased.Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45-0.59 g/g-dry biomass).Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = -0.95 to -0.97) with xylose concentration and acid-insoluble residue yield.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho, Nada-ku, Kobe, Hyogo, Japan.

ABSTRACT
A renewable raw material, rice straw is pretreated for biorefinery usage. Solution-state two-dimensional (2D) 1H-13 C hetero-nuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy, was used to analyze 13 cultivars of rice straw before and after dilute acid pretreatment, to characterize general changes in the lignin and polysaccharide components. Intensities of most (15 of 16) peaks related to lignin aromatic regions, such as p-coumarate, guaiacyl, syringyl, p-hydroxyphenyl, and cinnamyl alcohol, and methoxyl, increased or remained unchanged after pretreatment. In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased. Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45-0.59 g/g-dry biomass). Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = -0.95 to -0.97) with xylose concentration and acid-insoluble residue yield. These results showed the fate of lignin and polysaccharide components by pretreatment, suggesting that lignin aromatic regions and cellulose components were retained in the acid insoluble residues and starch-derived components were transformed into glucose, 5-HMF, and formate in the liquid hydrolysate.

No MeSH data available.


Related in: MedlinePlus

Fate of lignin and polysaccharides components in rice straws following dilute acid pretreatment.Lignin aromatic regions were retained in the acid insoluble residues. Starch-derived components positively affected glucose, 5-HMF, and formate concentrations in the liquid hydrolysate.
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pone.0128417.g007: Fate of lignin and polysaccharides components in rice straws following dilute acid pretreatment.Lignin aromatic regions were retained in the acid insoluble residues. Starch-derived components positively affected glucose, 5-HMF, and formate concentrations in the liquid hydrolysate.

Mentions: To further investigate the above-mentioned relationships observed in 2D 1H-13C HSQC-NMR analyses, the relationships between the glucose concentration and the concentrations of xylose, 5-HMF, and formate in the liquid hydrolysate and the relationship between the acid-insoluble residue yield and xylose concentration were investigated (Fig 6). As expected, the glucose concentration was positively correlated with the concentrations of 5-HMF and formate (r = 0.93 and 0.80, respectively) as 5-HMF is derived from hexoses and formate is derived from 5-HMF (and furfural) (Fig 6B and 6C) [36]. Interestingly, the glucose concentration negatively correlated with the xylose concentration (r = –0.97) in liquid hydrolysate (Fig 6A). This results suggested that fractionation between glucose and xylose is occurring in soluble sugars following dilute acid pretreatment (Fig 7). Also, the positive relationship (r = 0.96) between xylose concentration in the hydrolysate and the acid-insoluble residue yield (which is composed mainly of cellulose and lignin) (Fig 6D) was interesting because xylan in hemicellulose is the main source of xylose in the liquid hydrolysate. This results suggested that fractionation between glucose in soluble sugars and insoluble sugars following dilute acid pretreatment is also occurring, assuming that lignin content was constant (Fig 7).


Changes in Lignin and Polysaccharide Components in 13 Cultivars of Rice Straw following Dilute Acid Pretreatment as Studied by Solution-State 2D 1H-13C NMR.

Teramura H, Sasaki K, Oshima T, Aikawa S, Matsuda F, Okamoto M, Shirai T, Kawaguchi H, Ogino C, Yamasaki M, Kikuchi J, Kondo A - PLoS ONE (2015)

Fate of lignin and polysaccharides components in rice straws following dilute acid pretreatment.Lignin aromatic regions were retained in the acid insoluble residues. Starch-derived components positively affected glucose, 5-HMF, and formate concentrations in the liquid hydrolysate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470627&req=5

pone.0128417.g007: Fate of lignin and polysaccharides components in rice straws following dilute acid pretreatment.Lignin aromatic regions were retained in the acid insoluble residues. Starch-derived components positively affected glucose, 5-HMF, and formate concentrations in the liquid hydrolysate.
Mentions: To further investigate the above-mentioned relationships observed in 2D 1H-13C HSQC-NMR analyses, the relationships between the glucose concentration and the concentrations of xylose, 5-HMF, and formate in the liquid hydrolysate and the relationship between the acid-insoluble residue yield and xylose concentration were investigated (Fig 6). As expected, the glucose concentration was positively correlated with the concentrations of 5-HMF and formate (r = 0.93 and 0.80, respectively) as 5-HMF is derived from hexoses and formate is derived from 5-HMF (and furfural) (Fig 6B and 6C) [36]. Interestingly, the glucose concentration negatively correlated with the xylose concentration (r = –0.97) in liquid hydrolysate (Fig 6A). This results suggested that fractionation between glucose and xylose is occurring in soluble sugars following dilute acid pretreatment (Fig 7). Also, the positive relationship (r = 0.96) between xylose concentration in the hydrolysate and the acid-insoluble residue yield (which is composed mainly of cellulose and lignin) (Fig 6D) was interesting because xylan in hemicellulose is the main source of xylose in the liquid hydrolysate. This results suggested that fractionation between glucose in soluble sugars and insoluble sugars following dilute acid pretreatment is also occurring, assuming that lignin content was constant (Fig 7).

Bottom Line: In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased.Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45-0.59 g/g-dry biomass).Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = -0.95 to -0.97) with xylose concentration and acid-insoluble residue yield.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokkodaicho, Nada-ku, Kobe, Hyogo, Japan.

ABSTRACT
A renewable raw material, rice straw is pretreated for biorefinery usage. Solution-state two-dimensional (2D) 1H-13 C hetero-nuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy, was used to analyze 13 cultivars of rice straw before and after dilute acid pretreatment, to characterize general changes in the lignin and polysaccharide components. Intensities of most (15 of 16) peaks related to lignin aromatic regions, such as p-coumarate, guaiacyl, syringyl, p-hydroxyphenyl, and cinnamyl alcohol, and methoxyl, increased or remained unchanged after pretreatment. In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased. Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45-0.59 g/g-dry biomass). Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = -0.95 to -0.97) with xylose concentration and acid-insoluble residue yield. These results showed the fate of lignin and polysaccharide components by pretreatment, suggesting that lignin aromatic regions and cellulose components were retained in the acid insoluble residues and starch-derived components were transformed into glucose, 5-HMF, and formate in the liquid hydrolysate.

No MeSH data available.


Related in: MedlinePlus