Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LIGNIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources
PubMed2002

Cellulase production on bagasse pretreated with hot water.

Because pretreatment of biomass with hot water only in differential flow systems offers very digestible cellulose and potentially less inhibition by liquid hydrolysate, solids and liquid hydrolysate from bagasse pretreated with hot water were fed to a batch cellulase production system using the Rut C30 strain of Trichoderma reesei to determine the suitability of these substrates for cellulase production. The organism was found to be sensitive to inhibitors in the liquid hydrolysate but could be adapted to improve its tolerance. In addition, filtering of the material reduced inhibitory effects. The organism was also sensitive to some component in the solids, and they had to be washed heavily to achieve good growth and cellulase production rates. Even then, a lag was found before enzyme production would commence on pretreated solids whereas no such lag was experienced with Solka Floc. However, once enzyme production began, as high and even somewhat greater cellulase productivities were realized with washed pretreated solids. Adding lignin to Solka Floc delayed enzyme production, suggesting that lignin or other materials in the lignin solids could cause the lag observed for pretreated bagasse, but more studies are needed to resolve the actual reason for this delay.

Cellulase↗
PubMedDate not supplied

Degradation of biomacromolecules during high-rate composting of wheat straw-amended feces.

Pig (Sus scrofa) feces, separately collected and amended with wheat straw, was composted in a tunnel reactor connected with a cooler. The composting process was monitored for 4 wk and the degradation of organic matter was studied by two chemical extraction methods, 13C cross polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and pyrolysis gas chromatography-mass spectrometry (GC-MS). Wet-chemical extraction methods were not adequate to study the degradation of specific organic compounds as the extraction reagents did not give selective separation of hemicellulose, cellulose, proteins, and lignins. A new method was proposed to calculate the contribution of four biomacromolecules (aliphatics, proteins, polysaccharides, and lignin) from the 13C CPMAS NMR spectrum. Pyrolysis GC-MS allowed identification of the composition of the biomacromolecules. The biomacromolecules showed different rates of degradation during composting. High initial degradation rates of aliphatics, hemicellulose, and proteins were observed, where aliphatics were completely degraded and hemicellulose and proteins were partly recalcitrant during the four weeks of composting. The degradation rate of cellulose was much lower and degradation was not completed within the four weeks of composting. Lignin was not degraded during the thermophilic stage of composting but started to degrade slowly during the mesophilic stage. A combination of 13C CPMAS NMR and pyrolysis GC-MS gave good qualitative and semiquantitative assessments of the degradation of biomacromolecules during composting.

Animals↗
PubMed1997

Effect of six species of white-rot basidiomycetes on the chemical composition and rumen degradability of wheat straw.

This study was conducted to investigate changes in in vitro dry matter digestibility (IVDMD), volatile fatty acids (VFA) production and cell-wall constituent degradation in wheat straw treated with six white-rot fungi: Daedalea quercina, Hericium clathroides, Phelinus laevigatus, Inonotus andersonii, Inonotus obliquus, and Inonotus dryophilus. The incubation of wheat straw for 30 days at 28 C improved IVDMD from 41.4 (control) to 59.2% for D. quercina, 56.3% for H. clathroides, 50.2% for P. laevigatus, 51.4% for I. andersonii, 52% for I. obliquus, and 55.9% for I. dryophilus. In contrast, the growth of fungi was accompanied by the dry matter loss of wheat straw: 43% for D. quercina, 12% for H. clathroides, and 22-25% for the other fungi. It is evident that the increase in digestibility by D. quercina was not offset by a loss of dry matter. The total VFA production during the rumen fermentation of fungus-treated straw was slightly increased by H. clathroides and I. dryophilus only. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) were reduced in fungus-treated straw. Out of the three fractions (hemicellulose, cellulose, and lignin), hemicellulose and lignin showed the largest proportionate loss after inoculation with the fungi D. quercina, H. clathroides, P. laevigatus, and I. obliquus. The other two fungi showed the largest proportionate loss in cellulose and hemicellulose contents. The results of this study suggest that the digestion enhancement of wheat straw colonized by white-rot fungi is regulated by complex factors including the degradation of structural carbohydrates and lignin.

Journal Article↗
PubMed1999

Comparison of Tifton 85 and Coastal bermudagrasses for yield, nutrient traits, intake, and digestion by growing beef steers.

A study was undertaken to compare Tifton 85 (T85) and Coastal (CBG) bermudagrasses for effects of cultivar and age at harvest on yields of DM and digestible DM, in vitro digestion, nutrient content, cell wall composition, in situ digestion kinetics, and feed intake and digestion by growing beef steers. In Exp. 1, T85 and CBG forages staged for growth in May or July of 1993 were harvested at 3, 4, 5, 6, 7, and 8 wk from subplots. Tifton 85 bermudagrass had 7.1% greater DM yield, 18.2% higher (P < .05) digestible DM yield, and 7.1% greater IVDMD than CBG, and, after 5 wk of forage growth, IVDMD of both T85 and CBG decreased with increased age at harvest (P < .05). In Exp. 2, T85 and CBG forages staged for growth in July 1997 were harvested at 2, 3, 4, 5, 6, and 7 wk from subplots. Even though T85 had higher concentrations of NDF and ADF than CBG, T85 had 34.1% higher DM yield, 47.9% higher digestible DM, 55.0% higher digestible NDF, 91.7% higher digestible ADF, greater IVDMD, in vitro NDF and ADF disappearances, and higher in situ DM and NDF digestion (P < .05). Coastal bermudagrass had higher concentrations of lignin and lower concentrations of total neutral sugars, arabinose, glucose, and xylose than T85 (P < .05). In vitro digestibilities of DM, NDF, and ADF were lower and concentrations of ADF and lignin were greater for 7- vs 6-wk harvests of both T85 and CBG (P < .05). In Exp. 3, T85 and CBG forages staged for growth in July 1997 were harvested as hay at 3, 5, and 7 wk from .8-ha pastures and fed to 36 individually penned growing beef steers (initial BW = 244 kg) to quantify ad libitum intake without supplementation. Tifton 85 bermudagrass had lower concentrations of lignin and ether-linked ferulic acid and greater concentrations of NDF, ADF, hemicellulose, and cellulose than CBG (P < .05). Steers fed T85 had higher (P < .05) digestion of DM, OM, NDF, ADF, hemicellulose, and cellulose than steers fed CBG. Digestion of NDF, ADF, hemicellulose, and cellulose decreased (P < .05) with increased age at harvest for both cultivars. In conclusion, T85 produced more DM and had more digestible nutrients in vitro, in situ, and in vivo than CBG, and 3 and 5 wk of growth would be recommended ages to harvest either cultivar.

Animal Nutritional Physiological Phenomena↗
PubMed2004

Prediction of nutritive values in grass silages: I. Nutrient digestibility and energy concentrations using nutrient compositions and fermentation characteristics.

Grass silages (n = 136) were selected from commercial farms across Northern Ireland according to their pH, ammonia nitrogen, DM, and predicted ME concentration. Each silage was offered to four sheep as a sole feed at maintenance feeding level to determine nutrient digestibility and urinary energy output. Dry matter concentration was determined as alcohol-corrected toluene DM and was subsequently used as the basis for all nutrient concentrations. The objectives were to use these data to examine relationships between nutritive value and nutrient concentration or fermentation characteristics in silages and then develop prediction equations for silage nutritive values using stepwise multiple regression techniques. The silages had a large range in quality (DM = 15.5 to 41.3%, ME = 7.7 to 12.9 MJ/kg of DM, pH = 3.5 to 5.5) and a relatively even distribution over the range. There was a positive relationship (P < 0.001) between silage GE and DE or ME concentration. Digestible OM in total DM (DOMD); ME/GE; and digestibility of DM, OM, and GE were positively related (P < 0.05) to CP, soluble CP, ether extract, lactic acid concentration, and lactic acid/ total VFA, whereas they were negatively related (P < 0.05) to ADF, NDF, lignin, individual VFA concentration, pH, and ammonia N/total N. Concentrations of DE and ME and digestibility of CP and NDF had similar relationships with those variables, although some relationships were not significant. Three sets of multiple prediction equations for DE and ME concentration; ME/ GE; DOMD; and digestibility of DM, OM, GE, CP, and NDF were therefore developed using three sets of predictors. The first set included GE, CP, soluble N/total N, DM, ash, NDF, lignin, lactic acid/total VFA, and ammonia N/total N; the second set excluded soluble N/ total N and lignin because they are not typically measured; the third set further excluded the fermentation data. The R2 values generally decreased with exclusion of predictors. The second and third sets of equations, except for NDF digestibility, were validated using the mean-square-prediction-error model and an independent grass silage data set published since 1977 (n = 17 [DM digestibility] to 28 [DOMD and OM digestibility]). The validation indicated that the equations developed in the present experiment could accurately predict DE and ME concentrations and DE/GE and ME/GE in grass silages.

Animal Feed↗
PubMed1988

Effect of brown midrib and normal genotypes of sorghum X sudangrass on ruminal fluid and particulate rate of passage from the rumen and extent of digestion at various sites along the gastrointestinal tract in sheep.

The objectives of this experiment were to determine fluid and particulate rate of passage from the rumen and extent of digestion at various sites along the gastrointestinal tract in sheep fed normal and brown midrib sorghum X sudangrass hybrids. Four Suffolk wethers (80 kg) with ruminal, duodenal and ileal cannulae were assigned to one of four diets in a 4 X 4 Latin square with a 2 X 2 factorial arrangement of treatments. Diets were hays of two sorghum X sudangrass varieties, Redlan X Greenleaf and Redlan X Piper, and their corresponding brown midrib mutants. There were no compositional differences resulting from variety or genotype in lignin content or fiber components, although alkali-soluble phenolic acids were higher in normal genotypes than in brown midrib. Vanillin was lower, whereas para-coumaric acid was higher, in normal genotypes than in brown midrib mutants. Ruminal digestibility of neutral detergent fiber, acid detergent fiber and cellulose was lower (P less than .05) for normal genotypes than for the brown midribs. Total-tract digestibility of cellulose was higher (P less than .05) for brown midrib mutants than for corresponding normal genotypes. No quantitative differences in fiber composition or lignin content were detected between normal and brown midrib genotypes; however, differences in composition of alkali-soluble phenolic acids of the lignin fraction could explain differences in digestibility detected between the two genotypes.

Animal Feed↗
PubMed1987

Definition and analysis of dietary fibre.

The definition of dietary fibre as "non-starch polysaccharides plus lignin", that has now been widely accepted, is chemically more distinct than earlier definitions, but still implies some difficulties in its demarcation. In practice, analytical problems and limitations are important, since definition and analysis of dietary fibre are closely related. The delimitation towards more or less undigestible starch fractions, highly soluble polysaccharides, oligosaccharides, and undigestible protein is discussed, as well as phytate, tannins and some other components. Methods for analysis of dietary fibre are based on one or more of three different principles: 1) Weighing after removal of non-fibre components, 2) Colorimetric carbohydrate determinations 3) Specific determination of monomeric constituents by gas-liquid chromatography (GLC) or high performance liquid chromatography (HPLC). Gravimetric methods, using enzymatic degradation of protein and starch, are generally preferred for assay of total dietary fibre, or soluble and insoluble fibre separately. Colorimetric methods are used mainly for determining uronic acids as a measure of pectins. Detailed methods usually employ GLC determination of monomers after acid hydrolysis, but HPLC appear to develop as a convenient alternative. Uronic acids are determined separately by colorimetry or decarboxylation, and lignin usually as Klason lignin, i.e. acid insoluble material.

Chromatography, Gas↗
PubMed1991

Effects of rice bran fibre and cholestyramine on the faecal excretion of Kanechlor 600 (PCB) in rats.

1. As rice bran fibre binds Kanechlor 600 (PCB), the present study was conducted to determine whether the fibre stimulates rat faecal excretion of PCB in vivo. 2. In rats fed diets containing rice bran fibre, lignin and cholestyramine, the faecal excretion of PCB was increased. Total PCB excreted in rat faeces for groups fed diets of 10% (w/w) rice bran fibre, 10% fibre plus 5% lignin, 5% cholestyramine and 10% fibre plus 5% cholestyramine were 3.4, 3.7, 2.2 and 5.4 times as much, respectively, as that of control rats. The greatest effect on the faecal excretion of PCB was thus obtained with rice bran fibre plus cholestyramine. 3. In rats fed these diets, PCB concentration of the small intestine was significantly decreased to 25-50% of that of controls. PCB of spleen in rats fed diets of 10% fibre, 10% fibre plus 5% lignin and 10% fibre plus 5% cholestyramine also decreased to 50% of that of controls. However, PCB of other tissues were not affected.

Animals↗
PubMed1991

Digestion of cell wall components by dairy heifers fed diets based on alfalfa and chemically treated oat hulls.

Four Holstein heifers were used in a 4 X 4 Latin square design to measure total tract digestion of cell wall components from diets based on alfalfa haylage and alkaline hydrogen peroxide-treated oat hulls. Diets contained 90% forage and 10% concentrate. Treatments were diets containing 90, 70, 50, or 30% alfalfa haylage with treated oat hulls supplying the remainder of the forage portion. Total tract digestion of cell wall-associated uronic acids, arabinose, galactose, mannose, rhamnose, and lignin were not affected by forage source. Digestibilities of cell wall glucose and xylose increased with increasing level of dietary treated oat hulls, reflecting the positive effect of alkaline hydrogen peroxide treatment on cell wall digestion. Cellulose (ADF minus acid detergent lignin) digestibilities were similar to those for cell wall glucose, whereas hemicellulose (NDF minus ADF) digestibilities were similar to those for cell wall arabinose plus xylose. Low digestibilities of alfalfa cell wall xylose indicate that some cell wall structure inhibits the degradation of alfalfa xylans. Low degradabilities of core lignin, esterified p-coumaric acid, and esterified acetyl groups suggest that these components may be involved primarily in depressing fermentation of cell wall polysaccharides.

Animal Feed↗
PubMedDate not supplied

[Decomposition of natural aromatic structures and xenobiotics by fungi].

The review deals with transformation of natural and synthetic aromatic compounds by fungi (causative agents of white rot, brown rot, or soft rot, as well as soil filamentous fungi). Major enzyme types involved in the transformation of lignin and aromatic xenobiotics are discussed, with emphasis on activity regulation under the conditions of secondary metabolism and oxidative stress. Coupling of systems degrading polysaccharides/lignin and non-phenolic lignin structures (without the involvement of lignin peroxidase) is analyzed, together with non-enzymatic mechanisms (involving lipoperoxide free radicals, cation-radicals, quinoid mediators, or transition metal ions). Metabolic pathways resulting in the formation of aromatic and haloaromatic compounds in fungi are described. Consideration is given to the mechanisms of fungal adaptation to aromatic xenobiotics.

Biodegradation, Environmental↗
PubMed2004

[Temporal and spatial variations of chemical constituents in maize].

Study on the temporal and spatial variations of chemical constituents in maize showed that with the development of maize, the contents of total starch, crude protein and crude lipid in its kernel increased, while those of crude protein and crude lipid in its leaf and stem decreased. The content of fiber extracted by neutral agent and that of fiber and lignin in leaves and stems increased. The crude protein content of the top leaf was higher than that of the basal leaf, while the content of fiber extracted by neutral agent and that of fiber and lignin in the top leaf were lower than those of the basal leaf. The crude protein content of the top stem was higher than that of the basal stem, while the content of the fiber extracted by neutral agent and that of the fiber and lignin in the top stem were lower than those of the basal stem.

Dietary Fiber↗
PubMed2005

Cloning of a manganese peroxidase cDNA gene repressed by manganese in Trametes versicolor.

White-rot fungi have the following enzyme systems for lignin degradation: laccase, lignin peroxidase and manganese peroxidase. There are other types of peroxidases related to lignin degradation, one of which we have cloned a cDNA gene of manganese-repressed peroxidase (MrP) in Trametes versicolor isolated in South Korea. The mrp transcript level has been decreased by 1 micrometer of Mn(2+).

Amino Acid Sequence↗
PubMed1987

Homology among multiple extracellular peroxidases from Phanerochaete chrysosporium.

The extracellular peroxidases of Phanerochaete chrysosporium were separated into 21 proteins by analytical isoelectric focusing. Fifteen of these enzymes oxidized veratryl alcohol (lignin peroxidases) in the presence of H2O2. Six enzymes were Mn(II)-dependent peroxidases. The Mn(II)-dependent enzymes appeared and reached their maximal activity earlier than the lignin peroxidases in the cultures. Peptide mapping, amino acid analysis, and reaction against specific antibodies showed that all the Mn(II)-dependent peroxidases were probably products of one gene. A great degree of homology was also present among the various lignin peroxidases.

Amino Acids↗
PubMedDate not supplied

Molecular species of the antitumor and antiviral fraction from pine cone extract.

The most active fraction (Fr. VI) of antitumor and antiviral pine cone extract was subjected to chemical structure analysis. IR, UV, and ESR spectroscopies, in addition to chromatographic analysis on cellulose-TLC plates, reveal that the major component of Fr. VI includes structures belonging to the lignin family. A commercial alkali-lignin showed antiviral activity and granulocyte iodination stimulating activity as effective as those of Fr. VI, but had much weaker immunopotentiating activities, such as antitumor and antimicrobial activities and splenocyte stimulating activity. As a tentative conclusion, the active principle of Fr. VI might be complex(s) of lignin-like polyphenolic skeleton with a molecular matrix of unknown components.

Animals↗
PubMed1983

In vitro interaction of 7,12-dimethylbenz[a]anthracene and its biliary metabolites with dietary fiber.

This in vitro study examined the ability of various dietary fiber components to bind 7,12-dimethylbenz[a]anthracene (DMBA), a hydrocarbon carcinogen known to contaminate food. Bile salt solutions of DMBA were incubated with individual fiber materials under various conditions, and the degree of binding was assessed. Binding of DMBA from simple bile salt solution was greatest with delipidated bran greater than acid lignin greater than alpha-cellulose greater than unprocessed bran. Binding to acid lignin was slowly reversible, was constant within the pH range 4-8, and appeared independent of a bile salt-fiber interaction. Acid lignin bound DMBA from a mixed lipid-bile salt solution significantly, but less effectively than from pure bile salt solutions. DMBA biliary metabolites from Sprague-Dawley rats were bound less extensively to all the fiber materials than was the parent hydrocarbon, but following hydrolysis of the metabolites by beta-glucuronidase binding was significantly increased. These results indicate that there is considerable potential for dietary fiber to interact with DMBA and its metabolites in the lumen of the gastrointestinal tract, possibly influencing hydrocarbon carcinogen bioavailability.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2002

Fast and efficient alkaline peroxide treatment to enhance the enzymatic digestibility of steam-exploded softwood substrates.

The enzymatic digestibility of steam-exploded Douglas-fir wood chips (steam exploded at 195 degrees C, 4.5 min, and 4.5% (w/w) SO(2)) was significantly improved using an optimized alkaline peroxide treatment. Best hydrolysis yields were attained when the steam-exploded material was post-treated with 1% hydrogen peroxide at pH 11.5 and 80 degrees C for 45 min. This alkaline peroxide treatment was applied directly to the water-washed, steam-exploded material eliminating the need for independent alkali treatment with 0.4% NaOH, which has been traditionally used to post-treat wood samples to try to remove residual lignin. Approximately 90% of the lignin in the original wood was solubilized by this novel procedure, leaving a cellulose-rich residue that was completely hydrolyzed within 48 h, using an enzyme loading of 10 FPU/g cellulose. About 82% of the originally available polysaccharide components of the wood could be recovered. The 18% of the carbohydrate that was not recovered was lost primarily to sugar degradation during steam explosion.

Cellulose↗
PubMed2004

Role of oxidative enzymatic treatments on enzymatic hydrolysis of softwood.

The impact of oxidative modification and partial removal of lignin by laccase-mediator treatments on the enzymatic hydrolysis of steam-pretreated softwood (SPS) was evaluated. Two mediators, N-hydroxy-N-phenylacetamide (NHA) and its acetylated precursor, were oxidized by the laccase from Trametes hirsuta, and their effects on the activity of cellulolytic enzymes and on the hydrolysis yield of SPS were examined. Both simultaneous and sequential combinations of laccase-mediator treatments with commercial cellulases increased the sugar yield in the enzymatic hydrolysis of SPS. The maximal increase was 21% when a sequential treatment was applied. Laccase treatment alone was also shown to improve hydrolysis. NHA oxidized by laccase inhibited significantly the cellulases of Trichoderma reesei, but the presence of the solid substrate protected the activities against oxidative inactivation. Surface analysis of the lignocellulosic substrate before and after the laccase and cellulase treatments revealed an enrichment of lignin and an increase of carboxylic groups on the surface of the hydrolysis residue.

Amides↗
PubMed2004

Characterization of the bound residues of the fungicide cyprodinil formed in plant cell suspension cultures of wheat.

The non-extractable residues of the fungicide cyprodinil formed in heterotrophic cell suspension cultures of wheat were studied by application of [2-pyrimidyl-14C] or [2-pyrimidyl-13C]cyprodinil. The main objective was to examine whether solid-state and liquid 13C NMR spectroscopy can be used to examine plant bound residues of pesticides. For 14C experiments, wheat suspensions grown on glucose as carbon source were treated with 10 mg litre(-1) of 14C-cyprodinil. After incubation for 12 days, 20% of applied 14C was detected as non-extractable residues. The cell debris were treated with 0.1 M HCl (reflux), 1.0 M HCl (reflux), buffer, or 2 M NaOH (50 degrees C); Björkman lignin and acidolysis lignin fractions were also prepared from the debris. Radioactivity liberated and solubilized by these procedures was examined by thin-layer chromatography and high-performance liquid chromatography. The results showed that cyprodinil and primary metabolites contributed to the fungicide's bound residues. Most of the residues (12% of applied 14C) remained associated with polar or polymeric/oligomeric endogenous cell materials in a stable manner. For the study with 13C-cyprodinil, wheat suspensions were cultivated on 13C-depleted glucose for four growth cycles, resulting in maximum 13C depletion of the natural cell components to about 0.10%. During the fourth cycle, 13C-labelled cyprodinil was applied, and cells were incubated (12 days). Cell debris was prepared and examined by solid-state 13C NMR spectroscopy. Debris was then treated as described above in the 14C experiment. Solubilized fractions were analyzed by liquid 13C NMR spectroscopy. However, none of the 13C NMR spectra recorded gave utilizable or unambiguous results, and all exhibited large inconsistencies, especially concerning the data from the conventional 14C experiment.

Binding Sites↗