Showing papers on "Arabitol published in 2011"

Ergosterol, arabitol and mannitol as tracers for biogenic aerosols in the eastern Mediterranean

Abstract: . Aerosols containing biological components can have a significant effect on human health by causing primarily irritation, infection and allergies. Specifically, airborne fungi can cause a wide array of adverse responses in humans depending on the type and quantity present. In this study we used chemical biomarkers for analyzing fungi-containing aerosols in the eastern Mediterranean region during the year 2009 in order to quantify annual fungal abundances. The prime marker for fungi used in this study was ergosterol, and its concentrations were compared with those of mannitol and arabitol which were recently suggested to also correlate with fungal spores concentrations (Bauer et al., 2008a). Back trajectory analysis, inorganic ions, humidity and temperature were used in an attempt to identify sources as well as the dependence on seasonal and environmental conditions. We found that the ambient concentrations of ergosterol, arabitol and mannitol range between 0 and 2.73 ng m−3, 1.85 and 58.27 ng m−3, 5.57 and 138.03 ng m−3, respectively. The highest levels for all biomarkers were during the autumn, probably from local terrestrial sources, as deduced from the inorganic ions and back trajectory analysis. Significant correlations were observed between arabitol and mannitol during the entire year except for the winter months. Both sugars correlated with ergosterol only during the spring and autumn. We conclude that mannitol and arabitol might not be specific biomarkers for fungi and that the observed correlations during spring and autumn may be attributed to high levels of vegetation during spring blossoms and autumn decomposing.

Production of Arabitol from Glycerol: Strain Screening and Study of Factors Affecting Production Yield

Abstract: Glycerol is a major by-product from biodiesel production, and developing new uses for glycerol is imperative to overall economics and sustainability of the biodiesel industry. With the aim of producing xylitol and/or arabitol as the value-added products from glycerol, 214 yeast strains, many osmotolerant, were first screened in this study. No strains were found to produce large amounts of xylitol as the dominant metabolite. Some produced polyol mixtures that might present difficulties to downstream separation and purification. Several Debaryomyces hansenii strains produced arabitol as the predominant metabolite with high yields, and D. hansenii strain SBP-1 (NRRL Y-7483) was chosen for further study on the effects of several growth conditions. The optimal temperature was found to be 30°C. Very low dissolved oxygen concentrations or anaerobic conditions inhibited polyol yields. Arabitol yield improved with increasing initial glycerol concentrations, reaching approximately 50% (w/w) with 150 g/L initial glycerol. However, the osmotic stress created by high salt concentrations (≥50 g/L) negatively affected arabitol production. Addition of glucose and xylose improved arabitol production while addition of sorbitol reduced production. Results from this work show that arabitol is a promising value-added product from glycerol using D. hansenii SBP-1 as the producing strain.

Metabolism of glucose and xylose as single and mixed feed in Debaryomyces nepalensis NCYC 3413: production of industrially important metabolites

Abstract: Efficient conversion of hexose and pentose (glucose and xylose) by a single strain is a very important factor for the production of industrially important metabolites using lignocellulose as the substrate. The kinetics of growth and polyol production by Debaryomyces nepalensis NCYC 3413 was studied under single and mixed substrate conditions. In the presence of glucose, the strain produced ethanol (35.8 ± 2.3 g/l), glycerol (9.0 ± 0.2 g/l), and arabitol (6.3 ± 0.2 g/l). In the presence of xylose, the strain produced xylitol (38 ± 1.8 g/l) and glycerol (18 ± 1.0 g/l) as major metabolites. Diauxic growth was observed when the strain was grown with different combinations of glucose/xylose, and glucose was the preferred substrate. The presence of glucose enhanced the conversion of xylose to xylitol. By feeding a mixture of glucose at 100 g/l and xylose at 100 g/l, it was found that the strain produced a maximum of 72 ± 3 g/l of xylitol. A study of important enzymes involved in the synthesis of xylitol (xylose reductase (XR) and xylitol dehydrogenase (XDH)), glycerol (glycerol-3-phosphate dehydrogenase (G3PDH)) and ethanol (alcohol dehydrogenase (ADH)) in cells grown in the presence of glucose and xylose revealed high specific activity of G3PDH and ADH in cells grown in the presence of glucose, whereas high specific activity of XR, XDH, and G3PDH was observed in cells grown in the presence of xylose. To our knowledge, this is the first study to elaborate the glucose and xylose metabolic pathway in this yeast strain.

l -Arabinose pathway engineering for arabitol-free xylitol production in Candida tropicalis

Abstract: Xylose reductase (XR) is a key enzyme in biological xylitol production, and most XRs have broad substrate specificities. During xylitol production from biomass hydrolysate, non-specific XRs can reduce l-arabinose, which is the second-most abundant hemicellulosic sugar, to the undesirable byproduct arabitol, which interferes with xylitol crystallization in downstream processing. To minimize the flux from l-arabinose to arabitol, the l-arabinose-preferring, endogenous XR was replaced by a d-xylose-preferring heterologous XR in Candida tropicalis. Then, Bacillus licheniformisaraA and Escherichia coli araB and araD were codon-optimized and expressed functionally in C. tropicalis for the efficient assimilation of l-arabinose. During xylitol fermentation, the control strains BSXDH-3 and KNV converted 9.9 g l-arabinose l−1 into 9.5 and 8.3 g arabitol l−1, respectively, whereas the recombinant strain JY consumed 10.5 g l-arabinose l−1 for cell growth without forming arabitol. Moreover, JY produced xylitol with 42 and 16% higher productivity than BSXDH-3 and KNV, respectively.

Microbiological purification of L-arabitol from xylitol mother liquor.

Abstract: As a rare sugar alcohol, L-arabitol can be used in food and can prevent extra fat deposits in the intestinal tract. Commercially, L-arabitol is prepared from pure L-arabinose by hydrogenation, which needs a high temperature and high pressure, leading to a high production cost for Larabitol. Therefore, this study describes a novel L-arabitol production method based on biological purification from the xylitol mother liquor, a cheap and readily available raw material that contains a high concentration of Larabitol. First, a novel Bacillus megaterium strain was screened that can utilize xylitol, sorbitol, and mannitol, yet not L-arabitol. The isolated strain was inoculated into a medium containing the xylitol mother liquor under formulated culture conditions, where a high L-arabitol yield (95%) and high purity (80%) were obtained when the medium was supplemented with 50 g/l of xylitol mother liquor. Upon further purification of the fermentation broth by ion exchange and decolorization, L-arabitol was crystallized with a purity of 98.5%.

Production of arabitol

Abstract: A method for producing arabitol, and more particularly to producing arabitol in a major amount based on a total weight of all polyols produced and in relatively high concentration from a mixture including a carbon source such as glycerol. The method includes in one embodiment utilizing select yeast strains to produce arabitol in high yield while minimizing the amounts of other polyols, using carbon sources such as glycerol as a component in a medium. In a beneficial embodiment, biodiesel byproduct glycerol is used as the substrate for arabitol production.

Xylitol-producing strain to which an arabinose metabolic pathway is introduced, and method for producing xylitol using same

Abstract: The present invention relates to a method for efficiently producing xylitol, which suppresses the production of the by-product arabitol by applying arabinose to cell metabolism in a complex medium of xylose and arabinose using a xylitol-producing strain to which an arabinose metabolic pathway is newly introduced. More particularly, the present invention relates to a method for producing xylitol suppressing the production of arabitol, which hinders purification and crystallization during the production of xylitol, by performing codon optimization so as to effectively express the L-arabinose isomerase (araA), L-ribulokinase (araB), and L-ribulose-5-phosphate 4-epimerase (araD) enzymes in Candida tropicalis strains; then inserting respective genes into a cassette including a promoter of glyceraldehyde-3-phosphate dehydrogenase and a selectable marker URA3; and transferring the latter to Candida sp. The xylitol-producing strain to which an arabinose metabolic pathway is newly introduced of the present invention can suppress the production of arabitol and can thus be useful in producing xylitol at a high yield.

Xylitol Producing Microorganism Introduced with Arabinose Metabolic Pathway and Production Method of Xylitol Using the Same

Abstract: The present invention relates to an efficient production method of xylitol by using the xylitol producing microorganism introduced with arabinose metabolic pathway to inhibit the production of arabitol, the byproduct, and instead to use arabinose only for cell metabolism in xylose/arabinose mixed medium. More precisely, to express efficiently L-arabinose isomerase (araA), L-ribulokinase (araB) and L-ribulose-5-phosphate 4-epimerase (araD) in Candida tropicalis, codon optimization was performed. Then, each gene was inserted in the gene expression cassette containing the glyceraldehyde-3-phosphate dehydrogenase promoter and the selection marker URA3, which was introduced into Candida sp. microorganism. As a result, arabitol, the byproduct interrupting the purification and crystallization of xylitol could be inhibited, making the production method of xylitol of the present invention more efficient. The xylitol producing microorganism introduced with arabinose metabolic pathway of the present invention can be effectively used for the production of xylitol with high productivity by inhibiting the generation of arabitol.

Determination of Arabitol,Trehalose and Mannitol in the Fruit Bodies of Edible Fungi Using High Performance Anion Chromatography-Pulsed Amperometric Detection(HAPEC-PAD)

Abstract: A method for determining trehalose,mannitol and arabitol levels in the fruit bodies of 17 edible fungi using high performance anion chromatography-pulsed amperometric detection(HAPEC-PAD) is described.Samples could be tested without derivatization,and arabitol,trehalose and mannitol measurements were linear over the ranges 239.62-1.25,59.41-0.15 and 148.29-5.00 μg/mL,respectively.The limits of detection(LOD) for arabitol,trehalose and mannitol were 0.41,0.04 and 2.11μg/mL,respectively and the limits of quantification(LOQ) were 1.14,0.10 and 5.79 μg/mL,respectively.High levels of arabitol were recorded in Lentinula edodes and Hericium erinaceus,high levels of trehalose in Agrocybe aegerita,Pleurotus eryngii,Pleurotus abalonus,Tricholoma matsutake and Cordyceps militaris,and high levels of mannitol in Agaricus blazei,Cantharellus cibarius,Pleurotus citrinopileatus and Cordyceps sinensis.Our data demonstrate that HAPEC-PAD is an effective method for detecting these analytes in edible fungi,and provides a useful tool for research on their biological functions.

Composition for oral cavity and inhibitor of damage in gingival fibroblast caused by active oxygen

Abstract: PROBLEM TO BE SOLVED: To provide a composition for oral cavity and an inhibitor of damage in a gingival fibroblast caused by active oxygen that contain an ascorbic acid phosphoric ester salt, significantly inhibit cell damage which a gingival fibroblast constituting gums receives from active oxygen, and exhibit excellent preventive effects on periodontal diseases.SOLUTION: The composition for oral cavity is obtained by blending (A) an ascorbic acid phosphoric ester salt with (B) arabitol. The inhibitor of damage in a gingival fibroblast caused by active oxygen is composed of (A) the ascorbic acid phosphoric ester salt and (B) the arabitol.

Production of arabital

Abstract: A method for producing arabitol, and more particularly to producing arabitol in a major amount based on a total weight of all polyols produced and in relatively high concentration from a mixture including a carbon source such as glycerol. The method includes in one embodiment utilizing select yeast strains to produce arabitol in high yield while minimizing the amounts of other polyols, using carbon sources such as glycerol as a component in a medium. In a beneficial embodiment, biodiesel byproduct glycerol is used as the substrate for arabitol production.

Xylitol-producing strain to which an arabinose metabolic pathway is introduced, and method for producing xylitol using same

Abstract: The present invention relates to a method for efficiently producing xylitol, which suppresses the production of the by-product arabitol by applying arabinose to cell metabolism in a complex medium of xylose and arabinose using a xylitol-producing strain to which an arabinose metabolic pathway is newly introduced. More particularly, the present invention relates to a method for producing xylitol suppressing the production of arabitol, which hinders purification and crystallization during the production of xylitol, by performing codon optimization so as to effectively express the L-arabinose isomerase (araA), L-ribulokinase (araB), and L-ribulose-5-phosphate 4-epimerase (araD) enzymes in Candida tropicalis strains; then inserting respective genes into a cassette including a promoter of glyceraldehyde-3-phosphate dehydrogenase and a selectable marker URA3; and transferring the latter to Candida sp. The xylitol-producing strain to which an arabinose metabolic pathway is newly introduced of the present invention can suppress the production of arabitol and can thus be useful in producing xylitol at a high yield.