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1.
Peng Dangcong Jin Qiting 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,58(1):89-93
The anaerobic digestion of alkaline black liquor from a cereal straw pulping mill was studied in batch (serum bottles) and continuous systems (up-flow anaerobic sludge blanket reactor—UASB). The batch digestion studies confirmed that lignin and related compounds (LRC) in the alkaline black liquor were the main inhibitory substances and could not be decomposed by anaerobic bacteria. At organic loading rates of 5–10 kg COD m?3 day?1, the UASB reactor achieved 50–60% COD removal efficiencies. Gas production was 2–3 dm3 per dm3 of alkaline black liquor. Two different sludge types were examined in the reactor: granular and cluster-like sludges. Sludge in a cluster, which involved many small granules and flocs, tended to form larger aggregates and possessed good settling ability. 相似文献
2.
Pascale Mosoni Jean Michel Besle Marie Paule Maillot Liliane Gorrichon 《Journal of the science of food and agriculture》1994,64(2):145-154
[U-14C] phenylalanine (phe*) and [O14CH3] sinapic acid (sin*) were infused into the cut ends of normal and bm3 maizes (anthesis stage) under or above the last node or at mid-internode, with or without the leaf, in light or in darkness. Radioactivity was measured in the organs, and in phenolic constituents of the cell wall and saponified residues of the bases and tops of the apical inter-node. In both maize genotype labelled under the node the radioactivity was distributed more evenly in the organs with sin* than with phe*. Infusion above the node and at mid-internode greatly increased radioactivity in the bases and tops, respectively. Removal of the leaf only slightly increased the radioactivity, mainly in the bases, and no clear-cut effect of darkness was observed. Phe* labelled the phenolic acids and the three lignin units, but the syringyl units of bm3 maize were only slightly labelled. Sin* specifically labelled the syringyl units, which represented the least condensed fraction of lignins. Both the native and labelled lignins were highly alkali soluble. There were differences in lignin biogenesis between the bases and tops, and between normal and bm3 maizes. The newly formed lignins were slightly different from the native lignins but had similar types of heterogeneity, with variations in the internode and between genotypes similar to those in native lignins. Provided due allowance is made for the distinguishing characteristics of newly formed lignins, the [14C-lignin] cell walls, which are strongly labelled on complementary structures, seem suitable model substrates for fermentation studies. 相似文献
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该文概述了造纸工业的发展过程,分析探讨了我国造纸工业的现状、发展前景以及所面临的棘手问题,阐述了黑液中碱木素分级及低分子量木素分离的研究进展。提出了对于碱木素的研究手段,包括紫外分光光谱技术、红外光谱技术、^31P—NMR核磁共振波谱应用和凝胶渗透色谱技术(GPC)等等。 相似文献
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Guido C Galletti Paola Bocchini Ana M Smacchia James B Reeves III 《Journal of the science of food and agriculture》1996,71(1):1-9
Maize stovers collected every 14 days over an 84-day growth period were subjected to high-performance liquid chromatography with electrochemical detector (HPLC-ED) and pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS) in order to monitor changes in the phenolic composition. Prior to HPLC-ED analyses, ground samples were sequentially extracted with (i) methanol, (ii) 0·1M sodium hydroxide and (iii) 2M sodium hydroxide in the presence of nitrobenzene to separate, respectively, free phenolic monomers, alkali-labile phenolic monomers and alkali-resistant lignin. In turn, solution (ii) was treated with alkaline nitrobenzene to obtain (iv) alkali-labile lignin. Pyrolysis was carried out on ground native samples by using a platinum heated filament pyrolyser. Increases in the absolute phenolic concentrations in the residues of 0·1M sodium hydroxide extraction and in the ratio of alkali-resistant lignin vs total lignin were observed by HPLC-ED during the first 28–42 days of maturation, reaching a steady level in the remaining maturation period. A linear increase of syringyl units vs guaiacyl units was for found the alkali-resistant lignin fraction over the entire period of maturation. Similar trends were showed by PY/GC/MS with regard to relative lignin content and syringyl/guaiacyl ratio. Both techniques showed their usefulness to gauge changes in the phenolic composition during the lignification process. 相似文献
9.
Vincent J H Sewalt Wolfgang G Glasser Joseph P Fontenot Vivien G Allen 《Journal of the science of food and agriculture》1996,71(2):195-203
Experiments were conducted to determine whether formation of quinone methide intermediates from lignin occurs during ruminal fermentation of corn stover, as indicated by nucleophilic addition reaction with sulphur-containing reducing agents. Corn stover leaf and stem fractions harvested at full maturity were incubated in buffered ruminal fluid without reducing agents or with (NH4)2SO4 (S-control), Na2S.9H2O, cysteine-HCl (cysHCl), or cysHCl plus Na2S.9H2O; and in only buffer with or without cysHCl plus Na2S.9H2O. Mixed reducing agents (cysHCl plus Na2S.9H2O) enhanced ( P< 0.001) in vitro fibre degradation after 48 h, tended to increase solubilisation of fibre ( P =0.07) and dry matter ( P =0.06) in buffer alone, and elevated ( P< 0.001) S-content of residual fibre. In vitro incorporation of S into the undegraded fibre was determined for corn stover fractions of varying lignin compositions that were harvested at two maturities (early dent and full maturity) in 2 years. Extent of fibre degradation was correlated with extent of S-incorporation ( r =-0.54, P< 0.001), and with lignin methoxyl content ( r =-0.84, P< 0.001). The negative association of lignin methoxyl content with digestibility is explained by the relative likelihood of quinone methide intermediate formation from guaiacyl and syringyl units in lignin. 相似文献
10.
《Journal of Natural Fibers》2013,10(1):97-108
Abstract Spruce, coconut coir, sugarcane bagasse, kenaf bast, kenaf core, and cotton were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions as a function of their lignin content. The fibers were analyzed for sugar and lignin content and extracted with di-ethyl ether, ethyl alcohol, hot water, or 1% sodium hydroxide. The order of lignin content in un-extracted fibers is coconut coir > spruce > kenaf core > bagasse > kenaf bast > cotton. The fiber with the highest level of heavy metal removal was kenaf bast that had a very low level of lignin, showing that removal of heavy metals does not correlate with lignin content. Cotton, with about 1% lignin, was very low in metal ion sorption while all of the fibers containing lignin did remove heavy metal ions showing that lignin does play a role in metal ion sorption. Extraction with the various solvents removed different cell wall components and did change heavy metal sorption that indicates that cell wall chemistry and architecture may also be important factors in the sorption of heavy metals from aqueous solutions using lignocellulosic fibers. 相似文献