Lignocellulose is a promising starting material for bioproducts, ranging from biofuels to specialty chemicals; however, lignocellulose is resistant to enzymatic degradation. Overcoming this resistance is therefore an important priority for the development of the lignocellulosic biorefinery concept. In this work, 1-ethyl-3-methylimidazolium acetate ([emim]Ac) was selected from six ionic liquid candidates for the extraction of lignin from triticale and wheat straw and flax shives. Lignin extractability, composition, and cellulose enzymatic digestibility of the residues after extraction by [emim]Ac were determined at various temperatures (70-150 degrees C) and time intervals (0.5-24 h). The optimal result (52.7% of acid insoluble lignin in triticale straw) was obtained at 150 degrees C after 90 min, yielding >95% cellulose digestibility of the residue. Little cellulose was extracted, and the extracted lignin was recovered by acid precipitation. Selective extraction of lignin by ionic liquids is a potentially efficient technique for the comprehensive utilization of lignocellulose.

The polysaccharides, such as κ-carrageenan, ι-carrageenan, agarose (agar), gellan gum, amylose, curdlan, alginate, and deacetylated rhamsan gum, in water changed into an ice-like structure with hydrogen bonding between polymer and water molecules, and between water-water molecules even at a concentration range of 0.1%-1.0% (W/V) at room temperature, resulting in gelation. Such dramatic changes from liquid into gels have been understood at the molecular level in principles. In this review, we describe the structure-function relationship of starch on the view point of rheological aspects and discuss gelatinization and retrogradation mechanism including water molecules at molecular level. The starch molecules (amylose and amylopectin) play a dominant role in the center of the tetrahedral cavities occupied by water molecules, and the arrangement is partially similar to a tetrahedral structure in a gelatinization process. The arrangement should lead to a cooperative effect stabilizing extended regions of ice-like water with hydrogen bonding on the surface of the polymer molecules, where hemiacetal oxygen and hydroxyl groups might participate in hydrogen bonding with water molecules. Thus, a more extended ice-like hydrogen bonding within water molecules might be achieved in a retrogradation process. Though many investigations not only include starch gelatinization and retrogradaion, but also the gelling properties of the polysaccharides have been undertaken to elucidate the structure-function relationship, no other researchers have established mechanism at the molecular level. There is reasonable consistency in our investigations.

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To determine lignin content in triticale and wheat straws, calibration models were built using Fourier transform mid-infrared spectroscopy combined with partial least-squares regression. The best model for triticale and wheat straws was built using averaged spectra with raw spectrum in spectrum format and constant in path length as spectral pretreatments. The values of r(2), root-mean-square error of prediction (RMSEP), and residual predictive deviation (RPD) for the triticale straw model were 0.935, 0.305, and 3.89, respectively. The r(2), RMSEP, and RPD values for the wheat straw model were 0.985, 0.163, and 8.50, respectively. Both models showed good predictive ability. A model built using both triticale and wheat straws indicated that the values of r(2), RMSEP, and RPD were 0.952, 0.27, and 4.63, respectively. This model also showed good predictive ability and could predict lignin contents in triticale and wheat straws with the same high accuracy.

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A galactomannan isolated from seeds of Delonix regia was investigated. The specific rotation of the galactomannan was +15 degrees at 25 degrees C. The molecular mass of the galactomannnan was estimated to be 2.5 x 10(5). The ratio of D-mannose to D-galactose was estimated approximately to be 4.0:1.0 by HPLC and (1)H-NMR. NMR ((1)H and (13)C) spectra, and methylation analysis of the galactomannan indicated that it was composed of 1,4-linked beta-D-mannose, 1,4,6-linked beta-D-mannose, and terminal alpha-D-galactose. It was composed of pentasaccharide repeating-units, the chemical structure of which is proposed below.

We investigated macrophage activation by fucoidan from Laminaria angustata var. longissima in a murine macrophage cell line, RAW 264.7. The ratio of the chemical composition of the fucoidan was L-fucose: D-galactose:D-glucose:D-xylose:uronic acid:sulfate = 1.00:0.54:0.08:0.08:0.64:0.87. The fucoidan induced production of nitric oxide, tumor necrosis factor-, and interleukin-6 in RAW 264.7 cells. These results indicate that the fucoidan induced macrophage activation.Key words: Laminaria angustata var. longissima; fucoidan; macrophage activationFucoidan is a sulfated polysaccharide found in the cell-wall matrix of brown algae. There have been many reports that fucoidans from various brown algae have biological activities, such as anti-tumor, 1) anticoagulant, 2) anti-human immuno-deficiency virus, 3) and induction of apoptosis. 4) We have isolated a novel acetyl fucoidan from Cladosiphon okamuranus, 5,6) and have reported macrophage activation by acetyl fucoidan. 7)Macrophages are multifunctional cells that play significant roles in host defense. They phagocyte an invaded pathogen and produce inflammatory mediators and cytokines. Nitric oxide (NO), which is known to be an inflammatory mediator, is produced by the activation of inducible nitric oxide synthase (iNOS) from Larginine.8) NO has been reported to play an essential role in the cytolytic function, the killing of pathogens, and the tumoricidal action.9-11) Cytokines have an important role in the regulation of the inflammatory and immune responses.12) Polysaccharides isolated from plants and algae have been reported to enhance macrophage activation. 13-15)Laminaria angustata var. longissima is a brown alga eaten widely since 300 years ago in Okinawa, Japan. We have reported structural characteristics of fucoidans from L. angustata var. longissima.16) The fucoidans were obtained at about 1.4% w/w on the basis of dry matter, and they consisted of L-fucose, D-galactose, D-xylose, D-glucuronic acid, and sulfuric acid. We here investigated macrophage activation by the fucoidan in a murine macrophage cell line, RAW 264.7.Dulbecco's modified Eagle medium (DMEM), fetal bovine serum (FBS), penicillin, and streptomycin were purchased from Gibco BRL (Grand Island, NY). AntiiNOS rabbit IgG monoclonal antibody and anti--actin rabbit IgG polyclonal antibody were from Sigma (St. Louis, MO).The total carbohydrate and uronic acid of the fucoidan was analyzed by the phenol-sulfuric acid method 17) and the carbazole-sulfuric acid method 18) respectively. The sulfate content of the fucoidan was measured by the turbidimetric method. 19)The monosaccharides in the hydrolysate of the fucoidan were determined using high-performance anion exchange chromatography (DX-500, Dionex, Sunnyvale, CA), and fitted with a column of Carbopack PA1 and a pulsed amperometric detector. The column was eluted at a flow rate of 1 ml/min at 35 C with 15 mM NaOH for neutral sugar.The molecular mass of the fucoidan was measured by high-performance liquid chromatography (LC-6A; Shimadzu, Kyoto, Japan) wit...