Ivory Nut Research Articles

On-line quantitation of enzymatic mannan hydrolysates in small-volume bioreactors by microdialysis sampling and column liquid chromatography-integrated pulsed electrochemical detection

Quantitative aspects of on-line microdialysis sampling are investigated with respect to sampling in small-volume bioreactors. Three nodes of microdialysis sampling; continuous-flow microdialysis sampling (CFMS), stopped-flow microdialysis sampling with continuous stirring, and stopped-flow microdialysis sampling with stopped stirring were investigated as a possible means for studying bioprocesses. The hydrolytic properties of a well characterized endomannanase from Aspergillus niger were studied using 0.01% ivory nut mannan as substrate in a 5-ml reaction vessel. On-line sampling was achieved using a microdialysis probe fitted with an SPS 6005 membrane. Stopped-flow microdialysis sampling was found to give the least analyte depletion and thus used for quantitation of the enzymatic hydrolysates. However, CFMS can be used when analyte depletion is not significant (large-volume reactor). Hydrolysis of ivory nut mannan gave mainly mannobiose and mannotriose in almost equal amounts, which is consistent with an endo-wise hydrolysis. The concentrations of mannose and mannopentaose did not change significantly over the monitoring period, however, that of mannotetraose increased gradually up to 11 h where it starts to decrease.

The effects of utilization by people and livestock on Hyphaene petersiana (Arecaceae) basketry resources in the palm savanna of North-Central Namibia

Basketry production is an important informal sector activity in the palm savanna of north-central Namibia, particularly for women. This study assesses the comparative impact of utilization by basket makers and browsing livestock in areas of different human and livestock population pressures on the source of weaving fibre, leaves from juvenile individuals of the vegetable ivory palm,Hyphaene petersiana. Mature individuals of this species are an important source of edible fruit. Destructive uses of mature individuals such as tapping for palm wine and the cutting of stems for construction purposes are also practised, even though they are forbidden by customary law. Unlike other centres of basket production in southern Africa, the level of leaf utilization for basketry is low and there is potential for greater use of this resource. Despite the unpalatability of this species, a cause for concern, however, is the intensity of browsing by domestic livestock on young palms, which may affect the future structure and viability of the palm population in north-central Namibia. This predicted degradation of a multiple-use species such asH. petersiana represents the gradual erosion of an important buffer against rural poverty, loss of income and reduction in food security.

The impact of utilization of palm products on the population structure of the vegetable ivory palm (Hyphaene petersiana, arecaceae) in North-Central Namibia

Indigenous trees fulfil many subsistence and economic needs in north-central Namibia.Hyphaene petersiana provides a range of products which contribute to most aspects of people’s livelihoods. Of particular importance is its income-generating capacity through the use of palm leaves for basket production and the sale of liquor distilled from the fruits. This study investigates the population structure ofHyphaene petersiana in two areas of different human and livestock densities. Data were recorded for height class distribution, basal diameter of mature, stemmed individuals and sex ratios. These parameters of population structure indicate a reduction in the recruitment of mature palms and an increase in single-stemmed, vegetatively reproduced palm suckers of the smallest size class (0.5 m). This trend is more pronounced in the site with greater human and livestock population densities. It appears to be related to high recorded levels of browsing by livestock of juvenile, unstemmed palms, despite the unpalatability of palm leaves. This acts to prevent recruitment into larger size classes and increase the compensatory growth of palm suckers, the latter being enhanced due to reduced competition through the prior removal by grazing animals of grasses and other herbaceous species. Accompanying this heavy pressure on juvenile palms are destructive uses of mature, stemmed palms, including their felling for construction purposes and tapping for palm wine. With regional human population increase, exacerbated by a recent trend to privatise land and raise pressure on remaining communal resources, it is possible that these destructive uses of mature palms will increase to unsustainable levels. Concern is thus expressed in this study regarding the long-term viability ofHyphaene petersiana populatiops in this area.

Monitoring of enzymatic hydrolysis of ivory nut mannan using on-line microdialysis sampling and anion-exchange chromatography with integrated pulsed electrochemical detection

A new system for on-line monitoring of a small-scale bioprocess is described, based on microdialysis sampling and anion-exchange chromatography with integrated pulsed electrochemical detection. The microdialysis probe equipped with a 16-mm polysulfone membrane was used as an in situ sampling unit, giving a clean dialysate with no further need for sample clean-up. The system was used to continuously monitor the hydrolysis of 0.25% ivory nut mannan using endo-1,4-β-man-nanase (mannan endo-1,4- β-mannosidase; EC 3.2.1.78) from Aspergillus niger. The oligosaccharides produced in the hydrolysis, 1,4-β- d-mannobiose, mannotriose, mannotetraose, and mannopentaose, were separated isocratically and detected electrochemically. On-line monitoring of the hydrolysis of mannan using the endo-mannanase from A. niger, in a 5-ml reaction vessel, was achieved using 50 mM NaOH as mobile phase for 32 h without sampling or detection problems.

Purification and characterization of two β-mannanases from Trichoderma reesei

Five enzymes with mannanase activity were separated from Trichoderma reesei culture filtrate using analytical isoelectric focusing and subsequently detected with the zymogram technique. The crude enzymes had isoelectric points in the range of 3.6–6.5. Two of the mannanases with pI values of 4.6 and 5.4 were purified using ion-exchange chromatography, affinity chromatography and chromatofocusing. The molecular weights determined with SDS-PAGE were 51 000 (mannanase pI 4.6) and 53 000 (mannanase pI 5.4). The two enzymes had similar properties with respect to pH optimae and pH stabilities. Both mannanases hydrolyzed ivory nut mannan mainly to mannotriose and mannobiose. The specific activities (against locust bean gum) of the purified enzymes were 1860 and 1430 nkat mg −1 for the pI 4.6 and pI 5.4 mannanases, respectively.

13C NMR characterization of molecular structures in powders, hydrates and gels of galactomannans and glucomannans

Molecular structures present within powders, hydrates and gels of a range of galactomannans have been probed using high-resolution 13C NMR spectroscopy in both solid and solution states. As reference materials, ivory nut mannan (strong X-ray diffraction pattern of the mannan I polymorph) and gelled de-acetylated konjac glucomannan (weak mannan II diffraction pattern) have been utilized. Comparison of 13C spectral features suggests that hydrates, solutions and gels of galactomannans all contain mannan conformations similar to those in glucomannan gels. Chemical shift features characteristic of the mannan I form are observed for a dried and milled low-galactose galactomannan, although these features do not persist upon hydration. Dry powders of galatomannans have broad resonances probably due to the presence of a range of conformational states. Comparison of ‘solid-like’ and ‘solution-like’ spectral features in gelled samples suggests that relatively rigid chain segments are enriched in mannosyl residues for locust bean galactomannan and glucosyl residues of konjac glucomannan respectively.

The vegetable ivory industry: Surviving and doing well in Ecuador

Buttons made of vegetable ivory were once in great demand in industrial parts of the world. Vegetable ivory is the hard white seed endosperm from palms of the genusPhytelephas (Arecaceae). After World War II, ivory nuts were largely replaced by plastics. Recently the authors visited a factory on the coast of Ecuador that was founded in 1926 and still produces buttons of vegetable ivory on a large scale. Eighty employees produce about 5000 lb of buttons a month; these are exported to Japan, West Germany, and Italy. The production is described step by step and the future of vegetable ivory is discussed briefly.

13C CP/MAS NMR spectra of poly-β-D(1 → 4) mannose: mannan

13C solid-state NMR spectra (CP/MAS) were recorded for mannan polymorphs: mannan I ("ivory nut") and mannan II (Codiumfragile). These pure mannans, poly-β-(1 → 4) mannopyranose, show a single resonance for each carbon of the chemical repeat unit. This is the expected result based on the crystalline P212121 and 1222 symmetries. The T1 values were also recorded and the results are compared to those for cellulose obtained from the literature. The much lower mobility of C-6, even in noncrystalline mannan, compared to native cellulose is attributed to the epimeric difference at C-2 between cellulose and mannan allowing intramolecular hydrogen bonding in the former but not the latter. Keywords: mannan, solid state NMR, T1 relaxation, polysaccharide, ivory nut.

Thermal fragmentation analysis of neutral polysaccharides and the presence of 1,6-anhydrooligosaccharides

Small quantities of pyrolysates were obtained from micro-scale off-line pyrolysis of the neutral polysaccharides: cellulose, amylose, laminaran, nigeran, and a mannan from ivory nut. The pyrolytic fragments were analyzed by desorption chemical ionization – mass spectrometry, trimethylsilyl derivatization – capillary gas chromatography (– ammonia chemical ionization mass spectrometry) and benzoyl derivatization – high pressure liquid chromatography. Intact 1,6-anhydrohexosemonosaccharide, and -disaccharide fragments were identified as major products. By using off-line analytical pyrolysis information on saccharide composition can be obtained from the formation of anhydromonosaccharide products while linkage information is obtainable from distinctive anhydrodisaccharide products. Keywords: pyrolysis, polysaccharides, 1,6-anhydrooligosaccharides, desorption chemical ionization, mass spectrometry, gas chromatography, high pressure liquid chromatography.

Cell-wall-bound lytic activity in Chlorella fusca: function and characterization of an endo-mannanase

A cell-wall-degrading activity was solubilized from young cells and from mother cell walls of Chlorella fusca by treatment with LiCl. The cytoplasmic enzyme hexokinase was not detectable in these extracts. The LiCl-solubilized activity increased in the cell cycle parallel to the release of autospores. The enzyme was purified on a chromatofocusing column followed by gel filtration. Sodium dodecyl sulfate/polyacryl amide gel electrophoresis of the purified enzyme revealed a molecular weight of 44 kDa, whereas gel filtration indicated a molecular weight of 25 kDa. Cell-wall-lytic activity and β-1,4-mannanase activity coeluted in gel filtration and were separated from β-D-fucosidase activity. The enzyme degraded isolated cell walls and ivory nut mannan primarily to oligosaccharides with an estimated degree of polymerization ≧6. The soluble degradation products of the cell wall consisted of 92-96% mannose and 4-8% glucose. It is concluded that the cell-wall-lytic activity is caused by an endo-mannanase. In vivo, this enzyme probably degrades the mother cell wall and, after autospore release, remains bound to it as well as to the surface of the daughter cells by ionic forces. The identity of this bound enzyme with a soluble wall-degrading enzyme previously obtained from mother cells is discussed.

Structure and biochemistry of endosperm breakdown in date palm (Phoenix dactylifera L.) seeds

The zone of endosperm breakdown in the germinated date seed (Phoenix dactylifera L.) is a narrow area immediately adjacent to the surface of the enlarging cotyledon, or haustorium. The zone width is correlated with the amount of cell division in the adjacent region of the haustorium. The sequence of endosperm breakdown is: 1. protein bodies vacuolate, 2. storage cell walls become electron-transparent immediately adjacent to the protoplast of each endosperm cell, 3. all remaining cytoplasm and lipid bodies disappear, and 4. the remaining cell walls become electron-transparent and collapse against the haustorium surface. Two cell wall hydrolases are present—endo-Βmannanase (EC3.2.1.78) and Β-mannosidase (EC3.2.1.25). Β-mannosidase is detectable in the endosperm before germination. At germination, the major portion of activity is found in the softened endosperm. Β-mannanase is only detectable from germination and there is always hundreds of fold greater activity in the softened endosperm than elsewhere. Proteinase is detectable in trace amounts at germination in the softened endosperm but is also found in the haustorium at later stages. Isolated haustoria, incubated in extracted ivory nut (Phytelephas macrocarpa) mannan in buffer, cause no mannan breakdown. Haustoria, incubated in a solution of locust bean galactomannan, cause no decrease in galactomannan viscosity. Our observations suggest that although haustoria probably regulate mannan breakdown in the endosperm, they do not seem to secrete the hydrolytic enzymes concerned.

The crystalline polymorphism of mannan in plant cell walls and after recrystallisation

Mannan-rich plant cell walls were mechanically disintegrated and chemically extracted in order to ascertain their morphology and structure by electron microscopy and electron diffraction. For Acetabularia crenulata and Codium fragile, the cell-wall fragments were found to consist of alkali-resistant fibrillar mannan II encrusted with alkali-soluble granular mannan I. In the case of ivory nuts (Phytelephas macrocarpa) there is, in addition, a microfibrillar cellulose component which was also identified. The mannan I-mannan II polymorphism was also obtained when various mannan fractions were recrystallized from solution. In these recrystallizations, the occurrence of one or the other polymorph was found to depend on several parameters: the molecular weight of the mannan, the temperature of crystallization and the polarity of the crystallization medium.

Brontispa longissima . [Distribution map

Abstract A new distribution map is provided for Brontispa longissima (Gestro) (Col., Chrysomelidae). Host Plants: Coconut, betel, ivory nut and other palms. Information is given on the geographical distribution in ASIA, Indonesia, Taiwan, AUSTRALASIA, AND PACIFIC ISLANDS, Australia, Irian Jaya, New Caledonia, New Hebrides, Papua New Guinea, Society Islands, Solomon Islands.

Structural studies on triacetates of mannan and glucomannan

Mannan triacetates prepared from material extracted from ivory nut and Tubera salep were studied by means of electron and X-ray diffraction. The former is uniquely constituted of acetylated d-mannopyranosyl units linked by a (1 → 4)-β-linkage whereas the latter contains acetylated (1 → 4)-β- d-glucopyranosyl randomly distributed in the backbone with a ratio of mannose to glucose of about 3:1. However, there seems to be no effect on crystallisation due to the presence of the glucosidic units on the conformation of the chain. Single crystals of ivory nut triacetate were prepared by slowly cooling a dilute solution of nitromethane and butanol. The crystals were long narrow laths which provide electron diffraction data after annealing at 190°C in a vacuum. Two different unit cells were derived from the acetylated Tubera salep X-ray data. A first unit cell with a = 1·18 nm, b = 1·54 nm and c = 1·60 nm contains eight sugar units, whereas the second unit cell with a = 0.369 nm, b = 0·96 nm and c = 1·58 nm would accommodate 16 residues. The latter agrees best with the base-plane parameters derived from electron diffraction of single crystals. The X-ray fibre diagram was interpreted in terms of a two-fold helix and an asymmetric unit composed of two triacetyl mannopyranosyl units. This means that two chemically identical mannose units would not be conformationally equivalent along the backbone. The presence of glucose units in the backbone does not seem to perturb the crystalline conformation. The ‘isomorphous replacement’ hypothesis was invoked to explain this observation. The helical parameters derived herein for Tubera salep mannan triacetate are different from those reported earlier for the same acetylated glucomannan but crystallised using a different technique. This is attributed to the occurrence of polymorphism in this material.

Single crystals and oriented crystallization of ivory nut mannan

AbstractThe preparation of lamellar single crystals of mannan[poly((1 → 4)‐β‐D‐mannose)] is described. Electron diffractograms clearly identify the perpendicular orientation of the chain axis with respect to the lamellar surface. Since the degree of polymerization is 40 or less, no conclusion is made as to chain folding. The unit cell corresponds to the mannan I structure derived from x‐ray fiber data on oriented algal mannan. The baseplane dimensions found were a = 7.22 Å and b = 8.92 Å, and the systematic absences observed confirm the proposed P212121 group. It was found that cellulose microfibrils from Valonia ventricosa and bacterial cellulose could serve as extended chain nuclei for inducing oriented crystallization of mannan on cellulose. This produces a shish‐kebab type of morphology.

Präparative zugänge zu mannobiose und laminaribiose

Preparative approach to mannobiose and laminaribiose For synthetic purposes mannobiose is isolated from the polysaccharide mannan of ivory nut flower. The chain length of mannan A is determined to approximately 15 mannose units on average with a definite distribution from 5 to 25 mannose units. Acetolysis is optimized and yields 41% mannobiose. The separation on Sephadex G-15 yields pure mannobiose, and in addition its higher homologues in gram amounts. Detection of the eluates is performed using a differential refractometer. Correspondingly laminaribiose can be obtained from the polysaccharides laminaran (brown algae Laminaria hyperborea) and pachyman (fungus Poria cocos Wolf, Bukuryo) by selectively optimized acetolysis in 30% yield. Depending on the starting material separations are favourably performed on silica gel or on Sephadex G-15. Laminaribiose and its higher homologues are obtained in gram amounts.

Beta-Mannosidase from the mushroom Polyporus sulfureus.

beta-D-Mannosidase (EC 3.2.1.25), a useful tool for the structural studies of heterosaccharide chains, has been isolated in a highly purified form from the fruiting bodies of the mushroom Polyporus sulfureus. This mushroom is unique among reported sources of this enzyme in that it has the advantage of being almost free of alpha-mannosidase activity. The purification procedure involves ammonium sulfate fractionation followed by Sephadex G-100 filtration and chromatography on columns of DEAE-cellulose and hydroxylapatite. The final enzyme preparation gives essentially a single band on disc gel electrophoresis. The purified enzyme liberates the beta-D-mannopyranosyl unit from various natural substrates such as the core glycopeptide, Man(GlcNAc)2-Asn isolated from ovalbumin, from Taka-amylase A, and from human alpha1-acid glycoprotein. It also hydrolyzes (Man)2-GlcNAc from the urine of an alpha-mannosidosis patient, 1,4-D-mannobiose and mannotriose isolated from ivory nut mannan, 4-O-beta-D-mannopyranosyl-L-rhamnose, 6-O-beta-D-mannopyranosyl-D-galactose and 4-O-beta-D-mannopyranosyl-N-acetylglucosamine. The molecular weight of this enzyme is estimated to be about 64,000 by gel filtration. For p-nitrophenyl-beta-D-mannopyranoside, the pH optimum is between 2.4 and 3.4 and the Km is 1.6 mM.

Hydrolysis of Plant Mannans by Rumen Protozoal Enzvmes

Mannans or heteromannans (gluco-or galactoglucomannans) are commonly considered to be present in plants only in wood or associated with seeds. The present authors (Gaillard and Bailey 1968) have, however, recently isolated from the leaves and stems of red clover (Trifolium pratense) a polysaccharide fraction giving on hydrolysis galactose, glucose, mannose, and xylose (approximate ratios 1: 4�0: 2�0: 1�3), and which may, therefore, contain a mannan or heteromannan. This polysaccharide is designated "clover mannan" in the present work. Although apparently absent from grasses, such mannans may be common as minor constituents of pasture legume leaves and stems; for example, 1-2% of polymer mannose was reported present in lucerne (Hirst, MacKenzie, and Wylam 1959). Ivory nut (Phytelephas macrocarpa) mannan has been reported to be digested by ruminants (Beals and Lindsey 1916) and these pasture-plant mannans are probably also digested, presumably after hydrolysis by mannanases secreted by the rumen microflora. The only study of the action of rumen microorganisms on plant mannans appears to be that of Williams and Doetsch (1960), who isolated from the rumens of cows fed guaran (soluble galactomannan) several bacteria which could grow on this poly-saccharide and which secreted extracellular mannanase.

Non-cellulosic structural polysaccharides in algal cell walls - III. Mannan in siphoneous green algae

The cell walls of a number of green seaweeds, all members of the Codiaceae and the Dasy-cladaceae and includingCodiumandAcetabularia, are shown to containβ-1.4-linked mannan as the sole crystalline polysaccharide in the complete absence of cellulose. The X-ray diagram of the native mannan (almost identical with that of the mannan of ivory nut and of other palm-seed endosperms) has been indexed to an orthorhombic unit cella= 7.21 Å,b(fibre axis) = 10.27 Å,c= 8.82 Å. After treatment with alkali solutions the mannan recrystallizes in a different lattice; by analogy with cellulose we propose to name this form mannan II and the native mannan, mannan I. The lamellated walls of the central siphon of some of these algae (includingDasycladus,BatophoraandCymopolia) may be separated into two layers. X-ray diffraction analysis and polarization microscopy show that the mannan crystallites of the outer layer tend to lie transversely to the siphon axis, with some dispersion, while those in the inner layer lie longitudinally. The inner layers therefore yield good X-ray fibre diagrams from which a provisional structure of mannan I has been derived. It has proved impossible to reveal in the electron microscope, by the techniques used, the presence of true microfibrils in these plants even when the mannan is well oriented. Electron microscope images of carbon replicas reveal at most the appearance of short rodlets some 100 Å wide. The outer and inner layers resemble respectively the primary and secondary wall layers of higher plants. Some peculiar growth habits of members of the Dasycladaceae are discussed in terms of wall architecture.

On the structure of cell walls and cell wall mannans from ivory nuts and from dates

The submicroscopic structure of date and ivory-nut-endosperm cell walls has been studied with polarisation and electron microscopes. The structure of the two main components of these cell walls, mannan A and mannan B, has been investigated. Mannan A was found to be a granular material that was X-ray crystalline both in the native and in the isolated state. Native mannan B was found to be microfibrillar and to show birefringence; it was X-ray amorphous both before and after isolation and purification. The degree of polymerisation ( DP n ) of mannans A and B was determined osmometrically. This gave values between 17 and 21 for mannan A and about 80 for mannan B. The actual values, however, might be somewhat lower. Carbohydrate analyses of the isolated and purified mannan A showed only traces of galactose and glucose; mannan B after purification contained 6.6% of sugars other than mannose.