Showing papers on "Hemicellulose published in 1982"
TL;DR: The less-prominent bulking effect of guar gum and pectins, that were much more extensively fermented, could be only partly explained by dietary fibre and protein.
Abstract: 1. The fermentative breakdown of dietary fibre from various sources in the intestinal tract was studied using rat balance experiments and gas-liquid chromatograhic analysis of dietary fibre monomers in feed and faces. 2. On a basal diet with 690 g maize starch/kg but no added fibre, small but detectable amounts of polymeric glucose, rhamnose, arabinose, xylose, galactose, mannose and uronic acids, i.e. sugars occurring in dietary fibre, were excreted in faeces. 3. Dietary fibre in wheat bran was rather resistant to fermentation; 63% was recovered in the faeces. Guar gum, on the other hand, was almost completely fermented, whereas 19 and 25% of the uronic acids in low and high methoxylated pectin respectively, were excreted in faeces. The various constituents of sugar-beet dietary fibre (approximately equal amounts of arabinose-based hemicellulose, pectin and non-starch glucan (cellulose)) showed quite variable availability for micro-organisms in that 6-12% of the arabinose, 17-25% of the uronic acids, and 52-58% of the cellulose were recovered in the faeces. 4. Faecal nitrogen excretion increased on addition of any one of the dietary fibre preparations studied, resulting in decreased true and apparent protein digestibility values. 5. The faecal dry weight increment was most pronounced when feeding bran and could then almost be accounted for by the remaining fibre and by protein. The less-prominent bulking effect of guar gum and pectins, that were much more extensively fermented, could be only partly explained by dietary fibre and protein.
193 citations
TL;DR: In this article, the degradation of hemicelluloses and lignin-hemicelluose complexes from three varieties of grass of increasing maturity has been studied by using the cell-free hemiscale complex isolated from the ovine rumen.
142 citations
TL;DR: For example, this article found that fiber sources rich in hemicellulose and lignin (wheat bran, sunflower hulls) had high fat absorption properties, digestibility and serum triglycerides.
Abstract: Dietary fiber sources containing 31 – 99% of neutral detergent fiber were evaluated for functional properties and physiological effects on rats. The high water hydration capacity of mucilage-containing psyllium seeds and flax hulls were associated with low digestibility, high volume and weight of feces, and low serum triglycerides. Mustard hulls and sunflower heads, which contained less mucilage or pectin, were intermediate in water hydration capacity and as bulking agents in the gastrointestinal tract. Fiber sources rich in hemicellulose and lignin (wheat bran, sunflower hulls) had high fat absorption properties, digestibility and serum triglycerides. Pea hulls and cellulose showed less strong functional properties as sources of dietary fiber.
88 citations
TL;DR: The information presented in this publication represents current research findings on the production of glucose and xylose from straw and subsequent direct fermentation of both sugars to ethanol.
Abstract: The information presented in this publication represents current research findings on the production of glucose and xylose from straw and subsequent direct fermentation of both sugars to ethanol. Agricultural straw was subjected to thermal or alkali pulping prior to enzymatic saccharification. When wheat straw (WS) was treated at 170 degrees C for 30-60 min at a water-to-solids ratio of 7:1, the yield of cellulosic pulp was 70-82%. A sodium hydroxide extration yielded a 60% cellulosic pulp and a hemicellulosic fraction available for fermentation to ethanol. The cellulosic pulps were subjected to cellulase hydrolysis at 55 degrees C for production of sugars to support a 6-C fermentation. Hemicellulose was recovered from the liquor filtrates by acid/alcohol precipitation followed by acid hydrolysis to xylose for fermentation. Subsequent experiments have involved the fermentation of cellulosic and hemicelluosic hydrolysates to ethanol. Apparently these fermentations were inhibited by substances introduced by thermal and alkali treatment of the straws, because ethanol efficiencies of only 40-60% were achieved. Xylose from hydrolysis of wheat straw pentosans supported an ethanol fermentation by Pachysolen tannophilus strain NRRL 2460. This unusual yeast is capable of producing ethanol from both glucose and xylose. Ethanol yields were not maximal due to deleterious substances in the WS hydrolysates.
66 citations
TL;DR: In this article, conditions for pretreating aspen wood chips were optimized so that highest amounts of undegraded hemicellulose could be obtained after washing the steam exploded chips.
Abstract: Previously steam explosion had been used to enhance the enzymatic hydrolysis of lignocellulosic substrates to glucose. The conditions for pretreating aspen wood chips were optimized so that highest amounts of undegraded hemicellulose could be obtained after washing the steam exploded chips. The hemicellulose rich water soluble fractions showing highest pentosan yields were then acid hydrolysed to their composite sugars. Approximately 65–75% of the total reducing sugars detected in the wood hydrolysates were in the form of monosaccharides with D-xylose being the major component. Klebsiella pneumoniae was grown in media containing these wood hydrolysates as the substrate and 2,3-butanediol yields of 0.4–0.5 g per g of monosaccharide utilised were obtained.
62 citations
TL;DR: In this paper, the fermentation of carbohydrates and hemicellulose hydrolysate by Mucor and Fusarium species has been investigated, with the following results: both species are able to ferment various sugars and alditols, including d -glucose, pentoses and xylitol, to ethanol.
61 citations
TL;DR: The utilization of sugars present in wood hemicellulose by Klebsiella pneumoniae was investigated and production of 2, 3-butanediol was optimal under anaerobic conditions with all sugars tested, with the exception of D-xylose which appeared to require a finite air supply for maximal diol yield.
Abstract: The utilization of sugars present in wood hemicellulose byKlebsiella pneumoniae was investigated. Production of 2, 3-butanediol was optimal under anaerobic conditions with all sugars tested, with the exception of D-xylose which appeared to require a finite air supply for maximal diol yield. Anaerobic growth and solvent production of the organism on individual sugars revealed a similar pattern: diol production occurred generally at late exponential phase, concomitant with a culture off drop, and continued into stationary phase of growth. Solvent yields of 0.69 moles of 2, 3-butanediol and 0.69 moles of ethanol could be obtained per mole of D-glucose fermented anaerobically, while 0.45 moles of diol and 0.34 moles of ethanol were obtained per mole of xylose fermented under conditions of finite air supply.
57 citations
TL;DR: The addition of calcium carbonate to the media to enhance xylose utilized was beneficial although lower butanol values were obtained.
Abstract: Clostridium acetobutylicum was grown on a variety of different media and assayed for enhanced butanol production. Butanol values of about 90% of theoretical were obtained when glucose was used as the substrate. Five other sugars were assayed and the order of butanol production using these substrates was cellobiose>mannose>arabinose>xylose >galactose. The addition of calcium carbonate to the media to enhance xylose utilized was beneficial although lower butanol values were obtained.
57 citations
TL;DR: Tobacco pollen tubes grown in vitro and from pollinated tobacco styles were treated by chemical solvents to remove one or more of the following polysaccharides from the tube walls: pectin (ethylenediamine tetraacetic acid); hemicellulose (alkali); callose(alkali; potassium hypochlorite); cellulose (cuprammonium); and all polysacCharides with exception of cellulose.
Abstract: Tobacco pollen tubes grown in vitro and from pollinated tobacco styles were treated by chemical solvents to remove one or more of the following polysaccharides from the tube walls: pectin (ethylenediamine tetraacetic acid); hemicellulose (alkali); callose (alkali; potassium hypochlorite); cellulose (cuprammonium); and all polysaccharides with exception of cellulose (H2O2/glacial acetic acid). Both the inner tube wall, which we had regarded as the secondary wall, and the plugs contained, in addition to callose, microfibrils of cellulose and “non-cellulosic” microfibrils that had “pectin-like” properties. When using the expressions callosic or callose layer and callose plugs in reference to pollen tubes, one should realize that they do not imply the exclusive presence of callose in the inner tube wall layer and its localized thickenings.
55 citations
01 Mar 1982
TL;DR: In this paper, a rice straw was treated with NaOH, peracetic acid (PA), and sodium chlorite (NaClO2), and the results showed that the residual straw recovery rate after NaO2 treatment was lowest among the three chemical reagents evaluated.
Abstract: Rice straw was treated with NaOH, peracetic acid (PA), and sodium chlorite (NaClO2). Quantitative changes in the composition of the treated straw, crystallinity of the treated straw and extracted cellulose, and susceptibility of the treated straw to Trichoderma reesei cellulase were studied. The alkali treatment resulted in a remarkable decrease in hemicellulose as well as lignin. Consequently, the recovery of residual straw after NaOH treatment was lowest among the three chemical reagents evaluated. The treatment with PA or NaCIO2 resulted in a slight loss in hemicellulose and cellulose in the straw. The three chemical treatments caused little or no breakdown of the crystalline structure of cellulose in the straw. The treated straw was solubilized with the culture filtrate of T. reesei. The degree of enzymatic solubilization relative to the amount of residual straw was 69% after treatment with 0.25 N NaOH, 42% after treatment with 20% PA, and 50% after treatments with NaClO2 (twice). The degree of enzymatic solubilization relative to the amount of the untreated straw, however, was 30% after treatment with 0.25 N NaOH, 32% after treatment with 20% PA, and 37% after treatments with NaClO2 (twice).
51 citations
TL;DR: In this article, the equilibrium concentration of d -Xylose was determined for both isomerization and fermentation at pH 6.0, pH 5.3, and pH 6, pH 4.1.
TL;DR: In this paper, the α-amylase from porcine pancreas was used to identify the neutral detergent fiber (NDF) in wheat brans and oat cereals.
Abstract: Cereals are often promoted as important sources of dietary fiber. Ninety one breakfast cereals available in Canada and four unprocessed wheat brans were therefore analyzed for neutral detergent fiber (NDF) after rapid digestion with α-amylase from porcine pancreas. Many breakfast cereals contained less than 5% NDF. Wheat cereals contained 5–30% NDF, oat cereals contained 5% NDF, and corn and rice contained little NDF. Cereal NDF was predominantly hemicellulose (pentosans); pentose sugars liberated under hydrolysis represented up to 15% of processed bran cereals and 20–25% of unprocessed bran.
TL;DR: In this paper, the conversion of this cellulosic material to ethanol is discussed: the two-step process consisting of a hydrolysis step to glucose and the subsequent fermentation by yeasts; and the one step process, a fermentation of the cellulose by the anaerobic thermophile Clostridium thermocellum, or by a thermophilic, an-aerobic, defined mixed culture.
Abstract: An excess of organic waste, containing up to 60% cellulose and hemicellulose is produced worldwide. The conversion of this cellulosic material to ethanol is discussed: The two-step process consisting of a hydrolysis step to glucose and the subsequent fermentation by yeasts; and the one-step process, a fermentation of the cellulose by the anaerobic thermophile Clostridium thermocellum, or by a thermophilic, anaerobic, defined mixed culture. The use of the latter seems to be very feasible. To achieve an economic process, it is suggested to combine this approach with a thermophilic fermentation of the effluent and/or stillage obtained to produce methane.
TL;DR: The cell wall components of woody cells were examined at the ultrastructural level using enzymatic hydrolysis, delignification, steam pressure pulping and direct in situ localization by cytochemical methods as mentioned in this paper.
Abstract: The cell wall components of woody cells were examined at the ultrastructural level using enzymatic hydrolysis, delignification, steam pressure pulping and direct in situ localization by cytochemical methods. Based on the arrangement and localization of lignin, cellulose, hemicelluloses and pectic substances the already existing theories of three-dimensional wall architecture are discussed.
TL;DR: It appears that the millipede-bacterium association is mutualistic and makes available to millipedes an otherwise mostly unutilizable substrate that may be an important pathway for decomposition in desert ecosystems.
Abstract: I examined the role of aerobic microbial populations in cellulose digestion by two sympatric species of desert millipedes, Orthoporus ornatus and Comanchelus sp. High numbers of bacteria able to grow on media containing cellulose, carboxymethyl cellulose, or cellobiose as the substrate were found in the alimentary tracts of the millipedes. Enzyme assays indicated that most cellulose and hemicellulose degradation occurred in the midgut, whereas the hindgut was an important site for pectin degradation. Hemicellulase and beta-glucosidase in both species and possibly C(x)-cellulase and pectinase in O. ornatus were of possible microbial origin. Degradation of [C]cellulose by millipedes whose gut floras were reduced by antibiotic treatment and starvation demonstrated a reduction in CO(2) release and C assimilation and an increase in C excretion over values for controls. It appears that the millipede-bacterium association is mutualistic and makes available to millipedes an otherwise mostly unutilizable substrate. Such an association may be an important pathway for decomposition in desert ecosystems.
TL;DR: It has been shown that simultaneous attrition of cellulose in an attritor containing stainlesssteel beads results in a substantial enhancement of the enzymatic hydrolysis.
Abstract: It has been shown that simultaneous attrition of cellulose in an attritor containing stainlesssteel beads results in a substantial enhancement of the enzymatic hydrolysis. The attrition exerts two opposing effects, continuous delamination and comminution of the substrate with formation of new reactive sites and a gradual denaturation and inactivation of the enzyme. Consequently, the hydrolysis proceeds very rapidly at first and levels off at about 70% saccharification of the substrate. Accumulation of hydrolysis products is also responsible for inhibition of the enzyme. The attrition method is effective for the saccharification of cottonwood in which the cellulosic microfibrils are embedded in a matrix of lignin and hemicelluloses. A comparison between the saccharification of wood, lignocellulose, holocellulose, and cellulose with simultaneous attrition showed that the lignin component provided more hindrance toward the saccharification process than hemicelluloses, which are themselves subject to enzymatic hydrolysis.
TL;DR: Yeasts that ferment both D-cellobiose and D-xylose have been identified and may have advantages in the simultaneous saccharification and fermentation of cellulosics by obviating D- cellobiose inhibition of cellulase activity, and by allowing concurrent processing of the hemicellulose and cellulose.
Abstract: Yeasts that ferment both D-cellobiose and D-xylose have been identified. Such organisms may have advantages in the simultaneous saccharification and fermentation of cellulosics by obviating D-cellobiose inhibition of cellulase activity, and by allowing concurrent processing of the hemicellulose and cellulose.
TL;DR: In this article, an acid prehydrolysis with chemical delignification was studied as a method for fractionating lignocellulosic biomass into hemicellulose, lignin and cellulose.
Abstract: Acid prehydrolysis with chemical delignification was studied as a method for fractionating lignocellulosic biomass into hemicellulose, lignin and cellulose. Experiments with wheat straw show that hemicellulose can be quantatively separated by prehydrolysis, but the structure of the residue is substantially modified. Delignification of this residue by conventional methods gives significant losses of polysaccharides and a degraded cellulose. The efficiency of the separation can be increased by nonconventional delignification, e.g. chlorination by Cl. In this case, the sugar losses are minimal and further degradation of cellulose during delignification can be avoided, while lignin is quantatively recovered from the pulping liquors.
01 Jun 1982
TL;DR: The highest consumption with respect to total sugar (87%) and the best dry cell yield (15.6 g/l) were observed with the culture of Trichosporon cutaneum using the sugar solution obtained from the hemicellulose component.
Abstract: The components of rice straw, pretreated with sodium chlorite, cellulose and hemicellulose were solubilized with culture filtrate of Pellicularia filamentosa or Trichoderma reesei. The ratio of glucose to total sugar in the solution obtained from the cellulose component with the culture filtrate of Pellicularia filamentosa was approximately twice that of Trichoderma reesei. Ten yeast strains (Candida utilis, C. tropicalis, C. guilliermondii, C. parapsilosis, Torulopsis xylinus, Trichosporon cutaneum, Debaryomyces hansenii, Rhodotorula glutinis, Saccharomyces fragilis and Saccharomyces cerevisiae) were cultivated as test organisms for single-cell protein (SCP) production on sugar solutions obtained from the straw, cellulose and hemicellulose components, pretreated with the culture filtrate of Pellicularia filamentosa. Sugar consumption, in terms of total sugar and cell yield, of the culture with the sugar solution obtained from pretreated straw were; 70% and 6.8 g/l for Candida tropicalis, 56% and 6.4 g/l for Torulopsis xylinus, 76% and 10.1 g/l for Trichosporon cutaneum, and 74% and 7.6 g/l for Candida guilliermondii. In addition, the highest consumption with respect to total sugar (87%) and the best dry cell yield (15.6 g/l) were observed with the culture of Trichosporon cutaneum using the sugar solution obtained from the hemicellulose component.
TL;DR: In this paper, a graft copolymer was derived from hemicellulose-g-polyacrylonitrile (PAN) copolymers by extraction at room temperature with dimethylformamide and dimethylsulfoxide.
Abstract: Graft polymerizations of acrylonitrile onto both a commercial larchwood hemicellulose and a purified (low lignin) wheat straw hemicellulose could be initiated by ceric ammonium nitrate. The resulting hemicellulose-g-polyacrylonitrile (PAN) copolymers were fractionated by extraction at room temperature with dimethylformamide and dimethylsulfoxide. Fractions were characterized by determining both the wt % PAN in each polymer fraction and the molecular weight of grafted PAN. Saponification of the PAN component of hemicellulose-g-PAN gave a water-dispersible graft copolymer with good thickening properties for water systems. An absorbent polymer, similar to the starch-based absorbents (Super Slurpers), was produced when saponified hemicellulose-g-PAN was isolated by methanol precipitation and then dried. Larchwood hemicellulose was also graft-polymerized with methyl acrylate using ceric ammonium nitrate initiation, and the hemicellulose-g-poly(methyl acrylate) was extrusion-processed into a tough, leathery plastic. Although ceric ammonium nitrate could be used as an initiator for graft polymerizations onto low-lignin hemicelluloses, it was inert with crude wheat straw hemicellulose containing 11% lignin. The ferrous sulfate–hydrogen peroxide redox system was used to initiate graft polymerizations onto this high-lignin material, and properties of the resulting hemicellulose-g-poly(methyl acrylate) and saponified hemicellulose-g-PAN graft copolymers were evaluated.
TL;DR: In this article, the dietary fiber, cellulose, hemicellulose, lignin and pectic substances of 21 fruits have been determined for some varieties and different degrees of ripeness.
Abstract: The dietary fiber, cellulose, hemicellulose, lignin and pectic substances of 21 fruits have been determined. For some of these fruits several varieties and different degrees of ripeness have been considered. The contents of these compounds ranged between 0.2– 2.75% for dietary fiber, 0.06–1.8% for cellulose, 0.00–0.86% for hemicellulose, 0.06–0.5% for lignin and 0.12–1.28% for pectic substances. In some cases the dietary fiber can be affected by the fruit variety. Plantain increased in dietary fiber, hemicellulose and pectic substances content with increased ripening, while no change in cellulose and a decrease of lignin content were observed.
TL;DR: In this article, an infrared and ultra-violet spectroscopic analysis of nitric acid treated sugar maple and isolated wood polymers indicated extensive oxidation, nitration and hydrolysis of the wood polysaccharides and lignin.
Abstract: Previous research on chemical bonding has shown that a wood bond can be achieved by surface reactions when the wood is chemically activated prior to pressing. Activation by nitric acid appears to produce the most consistent results. The objective of this study was to elucidate the chemical mechanisms of nitric acid activation through the use of analytical instrumental techniques and identification of wood degradation products. Infrared and ultra-violet spectroscopic analysis of nitric acid treated sugar maple and isolated wood polymers indicated extensive oxidation, nitration and hydrolysis of the wood polysaccharides and lignin. The major effects were noted at ambient temperature although additional treatment at 100°C caused further modification. The lignin and xylan (hemicellulose) were the most extensively modified components as monitored by Klason lignin, Kjeldahl nitrogen and sugar analyses. Lignin is heavily nitrated and over 30% of the xylan (xylose) is lost during nitric acid treatment. T...
TL;DR: In this article, a batch delignification of southern yellow pine using aqueous solutions of ethanol and 1-butanol has been studied at a temperature of 175°C. The extent of delignization, hemicellulose hydrolysis of the pulp, and monosaccharide appearance in solution are reported.
Abstract: Batch delignification of southern yellow pine using aqueous solutions of ethanol and 1-butanol have been studied at a temperature of 175°C. The extent of delignification, hemicellulose hydrolysis of the pulp, and monosaccharide appearance in solution are reported. From these data the relationship of bulk delignification, hemicellulose behavior and solvent selectivity can be used to better explain pulp yield from alcohol: water treatment processes,
Patent•
05 Jul 1982
TL;DR: In this paper, a process and a device for separating hemicellulose and lignin from cellulose in lignocellulosic plant materials is described.
Abstract: The invention relates to a process and a device for separating hemicellulose and lignin from cellulose in lignocellulosic plant materials, for obtaining cellulose, optionally sugars and optionally soluble lignin. In a known embodiment it is only possible to degrade the three main components of the vegetable raw material in succession, for example in three reaction steps, by selecting the appropriate exposure temperatures and exposure times. It is the object of the invention to dissolve the hemicellulose and the lignin by conducting the process according to the invention, and to obtain a fibre which is essentially composed of cellulose. This object is achieved by treating the vegetable biomass in a pressurised container in a forced manner with pure water in the liquid state at temperatures of between 140 and 240 DEG C and a pressure of between 3.6 and 100 bar, the water and the vegetable biomass travelling through the pressurised container batchwise or continuously. Another essential aspect is that the residence time of the water in the pressurised container is between 10 and 200 seconds, preferably between 40 and 80 seconds.
TL;DR: In this paper, the alcohol insoluble residue (AIR) isolated from 12 foods was acid hydrolyzed and analyzed for neutral and acidic sugars, the predominant sugars present in the dietary fiber were arabinose, xylose, galactose, glucose and uronic acids.
Abstract: The alcohol insoluble residue (AIR) isolated from 12 foods was acid hydrolyzed and analyzed for neutral and acidic sugars. Aliquots taken at 1 hr were reduced, acetylated and analyzed for neutral sugar content with GLC. Glucose from cellulose, starch and non-cellulosic polysaccharides was analyzed with colorimetric methods. The predominant sugars present in the dietary fiber were arabinose, xylose, galactose, glucose and uronic acids. Pectin and hemicellulose together comprised the majority of cell wall polysaccharides. Samples high in starch generally contained the greatest amounts of dietary fiber and the least amount of water on a fresh plant basis.
Patent•
13 May 1982TL;DR: In this paper, a process for obtaining ethanol directly from D-xylose through fermentation of D-Xylose by xylose-fermenting yeast mutants is described. But this process requires the use of a mixture of cellulose and hemicellulose hydrolyzates.
Abstract: A process for obtaining ethanol directly from D-xylose through fermentation of D-xylose by xylose-fermenting yeast mutants. The process provides for obtaining ethanol from hemicellulose hydrolyzates through yeast fermentation of D-xylose to ethanol. In addition, a process for producing yeast mutants capable of utilizing D-xylose to ethanol in high yields is described. Furthermore, the process also provides for obtaining ethanol from a mixture of cellulose and hemicellulose hydrolyzates through yeast fermentation of D-glucose and D-xylose directly and simultaneously to ethanol.
TL;DR: In this article, a young bael ( Aegle marmelos ) tree with 2.5 m sodium hydroxide contained d -xylose and 4-O -methyl- d -glucoronic acid in the molar ratio of 7.43:1; traces of glucose, galactose, rhamnose and arabinose were also present.
01 Jan 1982
TL;DR: When incubated in combination with Trichoderma cellulase to convert cellulose to ethanol, HT4 displays a higher rate of ethanol production at 45/sup 0/C than at lower temperatures.
Abstract: Thermotolerant yeast, HT4, grows extensively in the temperature range of 30 to 45/sup 0/C. This yeast also ferments glucose at a high rate in the termperature range of 30 to 50/sup 0/C. When incubated in combination with Trichoderma cellulase to convert cellulose to ethanol, HT4 displays a higher rate of ethanol production at 45/sup 0/C than at lower temperatures. One of the benefits of using thermotolerant yeasts, such as HT4, is that cooling problems can be simplified during large-scale fermentations. 6 figures, 3 tables.
Journal Article•
TL;DR: The fermentation of leached beet pulp by the cellulolytic fungus Trichoderma reesei QM 9414 was studied under carbon limitation, with celluloses as the only carbon and energy source.
Abstract: Leached beet pulp is a plentiful waste in the sugar beet industry in Chile, reaching 100.000 metric tons per year on a dry basis. It represents an interesting substrate for protein upgrading through fermentation by cellulolytic organisms, because of the high content of cellulose and hemicellulose, with small amounts of protein and lignin (Table 1). The fermentation of leached beet pulp by the cellulolytic fungus Trichoderma reesei QM 9414 was studied under carbon limitation, with the celluloses as the only carbon and energy source. Nitrogen was supplied as ammonium sulphate and the medium was supplemented with other mineral salts as required for growth. Results on the kinetics of cellulose and hemicellulose degradation, level of reducing sugars in the medium, mycelial growth and production of cellulolytic enzymes are presented. Mycelial growth and related parameters were evaluated by an indirect method, based on nitrogen balances during fermentation. A yield of 0.26 g. of dry cell/g. of cellulosic substrate consumed and productivity of 0.095 g. of dry cell per liter per hour were obtained and compared with reported results on similar systems. After 40 to 45 hours of fermentation, approximately 80% of the cellulose and 45% of the hemicellulose were degraded (Fig. 2). Both, exoglucanase and endoglucanase, were induced; endoglucanase was growth associated, while exoglucanase appeared later in the growth phase, reaching its maximum activity in the stationary phase (Fig. 3). The product obtained was 30% protein and only 40 to 45% residual fiber, mostly hemicellulose. Mild acid hydrolysis has been successful in degrading hemicellulose but not cellulose, in the leached beet pulp.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: Investigations on the hemicellulose released from extractive-free, delignified pineapple leaf fiber revealed that it consists of (1→4)-linked d -xylopyranosyl residues in the main chain.