Showing papers on "Arabitol published in 2013"
TL;DR: In this paper, the fungal component of aerosol was studied at suburban/rural and at urban sites, and the results indicated that fungal spore concentrations were higher at the suburban and rural location and respectively inversely and directly proportional to temperature and relative humidity.
59 citations
TL;DR: Debaryomyces nepalensis, osmotolerant yeast isolated from rotten apple, is known to utilize both hexoses and pentoses and produce industrially important metabolites like ethanol, xylitol and arabitol.
Abstract: Debaryomyces nepalensis, osmotolerant yeast isolated from rotten apple, is known to utilize both hexoses and pentoses and produce industrially important metabolites like ethanol, xylitol and arabitol. In the present study, the effect of different growth substrates, trace elements, nitrogen concentration and initial pH on growth and formation of ethanol and arabitol were examined. Optimum conditions for maximizing the product yields were established: glucose as carbon source, an initial pH of 6.0, 6 g/L of ammonium sulphate and addition of micronutrients. Under these best suited conditions, a concentration of 11g/L of arabitol and 19 g/L of ethanol was obtained in shake flask fermentations. The fermentation was scaled up to 2.5 L bioreactor and the influence of aeration, agitation and initial substrate concentration was also determined. Under optimal conditions (150 g/L glucose, 400 rpm and 0.5 vvm) ethanol concentration reached 52 g/L, which corresponds to a yield of 0.34 g/g and volumetric productivity of 0.28 g/L/h, whereas arabitol production reached a maximum of 14 g/L with a yield and volumetric productivity of 0.1 g/g and 0.07 g/L/h respectively.
40 citations
TL;DR: The relationship between myc Cobionts and photobionts is, therefore, not commensalism, but mutualism with each other, as shown by d-NPQ expression.
Abstract: Lichens are drought-resistant symbiotic organisms of mycobiont fungi and photobiont green algae or cyanobacteria, and have an efficient mechanism to dissipate excess captured light energy into heat in a picosecond time range to avoid photoinhibition. This mechanism can be assessed as drought-induced non-photochemical quenching (d-NPQ) using time-resolved fluorescence spectroscopy. A green alga Trebouxia sp., which lives within a lichen Ramalina yasudae, is one of the most common green algal photobionts. This alga showed very efficient d-NPQ under desiccation within the lichen thallus, whereas it lost d-NPQ ability when isolated from R. yasudae, indicating the importance of the interaction with the mycobiont for d-NPQ ability. We analyzed the water extracts from lichen thalli that enhanced d-NPQ in Trebouxia. Of several sugar compounds identified in the water extracts by nuclear magnetic resonance (NMR), mass spectrometry (MS) and gas chromatography (GC) analyses, only d-arabitol recovered d-NPQ in isolated Trebouxia to a level similar to that detected for R. yasudae thallus. Other sugar compounds did not help the expression of d-NPQ at the same concentrations. Thus, arabitol is essential for the expression of d-NPQ to dissipate excess captured light energy into heat, protecting the photobiont from photoinhibition. The relationship between mycobionts and photobionts is, therefore, not commensalism, but mutualism with each other, as shown by d-NPQ expression.
29 citations
TL;DR: It is shown here that SP is already optimised to outcompete water as an acceptor substrate, meaning that it will be very difficult to lower its hydrolytic activity any further.
Abstract: Sucrose phosphorylase (SP) is a promising biocatalyst for the production of special sugars and glycoconjugates, but its transglycosylation activity rarely exceeds the competing hydrolytic reaction. Knowing how specificity is controlled, would allow to optimise this activity in an efficient way by means of enzyme engineering. Therefore, in this study, a map of the acceptor site of the SP from Bifidobacterium adolescentis was created by substituting each residue by alanine and analysing the influence on the affinity for both the natural (inorganic phosphate and fructose) and alternative acceptors ( d -arabitol and pyridoxine). All residues examined were found to contribute to the specificity for phosphate (Arg135, Leu343, Tyr344), fructose (Tyr132, Asp342) or both (Pro134, Tyr196, His234, Gln345). Alternative acceptors that are glycosylated rather efficiently (e.g. d -arabitol) were found to interact with the same residues as fructose, whereas poor acceptors like pyridoxine do not seem to make any specific interactions with the enzyme. Furthermore, it is shown here that SP is already optimised to outcompete water as an acceptor substrate, meaning that it will be very difficult to lower its hydrolytic activity any further. Consequently, increasing the transglycosylation activity towards alternative acceptors seems to be the best strategy, although that would probably require a drastic remodelling of the acceptor site in most cases.
25 citations
TL;DR: The pH, dissolved oxygen concentration (DO), inoculum size and magnesium concentration, and the nitrogen-to-phosphorus (N/P) ratio were systematically evaluated for effects on cell growth rate and arabitol productivity and it was found that the medium with N/P = 9, DO of 5% air saturation and pH 3.5 supported the highestArabitol production.
23 citations
TL;DR: In this article, the photocatalytic H2 evolution by Pt-loaded TiO2 was examined using sacrificial agents such as 1,2-ethanediol, glycerol, erythritol, and arabitol, the carbons of which all have hydroxy groups.
Abstract: The photocatalytic H2 evolution by Pt-loaded TiO2 was examined using sacrificial agents such as 1,2-ethanediol, glycerol, erythritol, and arabitol, the carbons of which all have hydroxy groups. In ...
21 citations
TL;DR: The fungus Fusarium sp.
Abstract: The fungus Fusarium sp. isolated from saline soil was identified by the ITS1-5.8S-ITS2 and the D1/D2 domains of LSU RNA as a member of the Fusarium incarnatum-equiseti species group. Its growth patterns on media with different NaCl concentrations indicated its adaptation as halotolerance. The mechanisms of halotolerance included accumulation of arabitol (a five-atom noncyclic polyol), a decreased sterols/phospholipids ratio, elevated level of phosphatidic acids in the phospholipids, and increased unsaturation of phospholipids, which was especially pronounced in the idiophase. The mechanisms of halotolerance of the mycelial fungus Fusarium sp. are discussed in comparison with yeasts and yeastlike fungi.
19 citations
TL;DR: In this article, the crystallization process of l -arabitol was investigated using differential scanning calorimetry (DSC) and X-ray diffraction, which enabled to show that the nucleation and growth domains were clearly separated and a metastable polymorph of lower melting point was obtained.
18 citations
TL;DR: Successful arabitol purification was achieved with an optimized process and fundamental phase equilibrium data of glycerol-xylitol-acetone systems were obtained.
Abstract: BACKGROUND
Arabitol has many potential industrial applications and it can be produced by fermentation from glycerol, a major byproduct of biodiesel industry. This work aims at developing a new process for collecting and purifying arabitol from the broth of osmophilic Debaryomyces hansenii containing arabitol, unconsumed glycerol, and other minor impurities. RESULTS: The process developed and optimized in this study had the following steps: first, the broth supernatant was treated with 8 g L−1 activated carbon at 30°C and pH 6 for removal of colored organics and some impurities. Then glycerol was selectively removed by acetone extraction at 30°C. The acetone amount was optimized according to the measured solubility data of simulative glycerol-xylitol-acetone systems and real fermentation broth. The glycerol-removed remainder was next extracted for arabitol with butanol (90% of supernatant volume) at 90 °C. White arabitol crystals were collected from the cooled butanol extract. The overall recovery and purity of arabitol crystals were 66% and 95%, respectively.
CONCLUSION
Successful arabitol purification was achieved with an optimized process. Fundamental phase equilibrium data of glycerol-xylitol-acetone systems were obtained. The process developed would prove valuable for arabitol production and potentially for separation of other polyols. © 2012 Society of Chemical Industry
15 citations
TL;DR: The aim of this study was to use statistical response surface methodology (RSM) to optimize the biotransformation of L-arabinose to arabitol by Candida parapsilosis, a yeast species able to assimilate pentoses.
Abstract: L-arabitol, a polyol with applications in the food and pharmaceutical industries, is secreted by different yeasts, e.g., Candida spp., Pichia spp., and Debaryomyces spp. The process of its biotechnological production is highly dependent on the physical and chemical conditions of culture. The aim of this study was to use statistical response surface methodology (RSM) to optimize the biotransformation of L-arabinose to arabitol by Candida parapsilosis, a yeast species able to assimilate pentoses. Batch cultures of the yeast were prepared following a Plackett-Burman design for seven variables. Following this, rotation speed, temperature, and L-arabinose concentration were chosen for a central composite design (CCD) experiment, which was carried out to optimize the production L-arabitol. The results showed that the optimal levels for the three factors were: rotation speed 150 rpm, temperature 28°C, and L-arabinose concentration 32.5 g/l. The predicted concentration of arabitol after two days of incubation of C. parapsilosis under the above conditions was 14.3 g/l. The value of R2=0.8323 suggested that this model was well-fitted to the experimental data, and this was confirmed during a verification experiment.
10 citations
Patent•
03 Apr 2013
TL;DR: Results obtained from this study clearly indicate that d-ribose is best substrate for ArDH for the production of sugar alcohols.
Abstract: Background: Arabitol dehydrogenase (ArDH) is involved in the production of different sugar alcohols like arabitol, sorbitol, mannitol, erythritol and xylitol by using five carbon sugars as substrate. Arabinose, d-ribose, d-ribulose, xylose and d-xylulose are known substrate of this enzyme. ArDH is mainly produced by osmophilic fungi for the conversion of ribulose to arabitol under stress conditions. Recently this enzyme has been used by various industries for the production of pharmaceutically important sugar alcohols form cheap source than glucose. But the information at structure level as well as its binding energy analysis with different substrates was missing. Results: The present study was focused on sequence analysis, insilico characterization and substrate binding analysis of ArDH from a fungus specie candida albican. Sequence analysis and physicochemical properties showed that this protein is highly stable, negatively charged and having more hydrophilic regions, these properties made this enzyme to bind with number of five carbon sugars as substrate. The predicted 3D model will helpful for further structure based studies. Docking analysis provided free energies of binding of each substrate from a best pose as arabinose -9.8224calK/mol, dribose -11.3701Kcal/mol, d-ribulose -8.9230Kcal/mol, xylose -9.7007Kcal/mol and d-xylulose 9.7802Kcal/mol. Conclusion: Our study provided insight information of structure and interactions of ArDH with its substrate. These results obtained from this study clearly indicate that d-ribose is best substrate for ArDH for the production of sugar alcohols. This information will be helpful for better usage of this enzyme for hyper-production of sugar alcohols by different industries.
TL;DR: Three mutants were constructed by homologous transformation into A. oryzae P4 (∆pyrG) using pyrG as a selectable marker to generate mutants with decreased dehydrogenase activities and increased xylitol production.
Abstract: Xylitol dehydrogenase (XDHA) and l-arabitol dehydrogenase (LADA) are two key enzymes in xylan metabolism catalyzing the oxidation of xylitol to d-xylulose and arabitol to l-xylulose, respectively. In Aspergillus oryzae, XDHA and LADA are encoded by xdhA and ladA. We deleted xdhA and ladA and xdhA–ladA to generate mutants with decreased dehydrogenase activities and increased xylitol production. The mutants were constructed by homologous transformation into A. oryzae P4 (∆pyrG) using pyrG as a selectable marker. The xylitol productivity of the mutants was measured using d-xylose as the sole carbohydrate source. xdhA, ladA, and the double-deletion mutant produced, respectively, 12.4 g xylitol/l with a yield of 0.24 g/g d-xylose, 12.4 g/l with a yield of 0.33 g/g d-xylose, and 8.6 g/l at a yield of 0.26 g/g d-xylose.
Dissertation•
31 May 2013
Patent•
16 Jan 2013
TL;DR: In this article, a method for preparing arabitol by flammulina velutipes was proposed, which utilizes the characteristic that flammula velutica sporocarp contains rich arabbitol to prepare the low-cost and environment-friendly arabititol by taking the flammuloin veluticas as a raw material; the product can be taken as natural sweetener and functional food raw material.
Abstract: The invention relates to a method for preparing arabitol by flammulina velutipes, which utilizes the characteristic that flammulina velutipes sporocarp contains rich arabitol to prepare the low-cost and environment-friendly arabitol by taking the flammulina velutipes sporocarp as a raw material; and the product can be taken as natural sweetener and functional food raw material. The method comprises the steps of: drying the fresh flammulina velutipes sporocarp, and then using high-concentration alcohol to soak or carry out reflux extraction on the dried flammulina velutipes sporocarp; carrying out vacuum concentration on the leach liquor to recover ethanol; putting the concentrated solution in the environment of 0-10 DEG C; separating out the arabitol by crystallization; filtering or centrifuging while the arabitol is cool to obtain arabitol crystal; then, carrying out recrystallization on the arabitol crystal by methanol; continuously carrying out vacuum concentration on the separated mother liquor of the crystal to recover ethanol; and repeating the operation of crystallization and recrystallization to improve the yield of the arabitol. In order to save the cost, the method is more suitable for taking defective flammulina velutipes sporocarp or the head cut from the flammulina velutipes sporocarp as raw material. The technology has the characteristics of being simple in equipment, saving the cost and protecting the environment, thus improving the economic benefit of the flammulina velutipes industry.
Patent•
03 Jul 2013
TL;DR: Xylitol and D-arabitol are important functional sugar alcohol, and have high application values in industrial production and life as discussed by the authors, and the main production methods for arabitol and xylitol comprises the step of subjecting the carbohydrate to catalytic hydrogenation at a high temperature under a high pressure to obtain target products, and the production technology has the defects of high energy consumption, serious pollution and the like.
Abstract: Xylitol and D-arabitol are important functional sugar alcohol, and have high application values in industrial production and life. At present, the main production methods for arabitol and xylitol comprises the step of subjecting the carbohydrate to catalytic hydrogenation at a high temperature under a high pressure to obtain target products, and the production technology has the defects of high energy consumption, serious pollution and the like. According to the invention, TIB-X229 of Pichia anomala which is CGMCC (china general microbiological culture collection center) No. 5482 and can produce the D-arabitol and the xylitol simultaneously is provided through separation, and a method for utilizing the yeast to transform a substrate containing glucose and/or xylose to produce the D-arabitol and the xylitol is also provided. The method utilizing the yeast to produce the sugar alcohol has the advantages of simple technology, convenience in product extraction, low cost and significant application value, and especially has a practical significance in the sugar alcohol production technology through transformation of cheap biomass raw materials.
01 Jan 2013
TL;DR: In this paper, the contents of erythritol,mannitol and arabitol in edible fungal mycelia are analyzed by the method of high performance anion chromatography-pulsed amperometric detection (HAPEC-PAD).
Abstract: The contents of erythritol,mannitol and arabitol in edible fungal mycelia are analyzed by the method of high performance anion chromatography-pulsed amperometric detection(HAPEC-PAD).Methodology of detecting erythritol is specially investigated and it is found that this method shows high sensitivity,separability and efficiency.The contents of alditols in mycelium of different edible fungal species were found to be variable.Using this method,corbrin capsule is also tested and the results show that the main alditol contained is erythritol but not mannitol.These studies could be regarded as the foundation for quality standardization of alditols in fungal mycelia.
01 Jan 2013
TL;DR: In this paper, the contents of erythritol, mannitol and arabitol in edible fungal mycelia are analyzed by the method of high performance anion chromatography-pulsed amperometric detection (HAPEC-PAD).
Abstract: The contents of erythritol, mannitol and arabitol in edible fungal mycelia are analyzed by the method of high performance anion chromatography-pulsed amperometric detection (HAPEC-PAD). Methodology of detecting erythritol is specially investigated and it is found that this method shows high sensitivity, separability and efficiency. The contents of alditols in mycelium of different edible fungal species were found to be variable. Using this method, corbrin capsule is also tested and the results show that the main alditol contained is erythritol but not mannitol. These studies could be regarded as