Arabitol

About: Arabitol is a research topic. Over the lifetime, 388 publications have been published within this topic receiving 8398 citations. The topic is also known as: D-(+)-Arabitol & D-arabitol.

Characterization as glycerol of an inhibitor of pectin lyases from autolysing cultures of Botrytis cinerea

Abstract: The protein-tannic acid precipitate from autolysed culture filtrates of Botrytis cinerea contained activities of pectin lyase and endo-pectin lyase. Both activities were inhibited by a substance present in the tannic acid precipitate. The substance was separated from the precipitate by dialysis and characterised by paper and gas-liquid chromatography as glycerol. Inhibition was detected at concentrations as low as 1 mM glycerol, and the effect increased with concentration to a maximum at approximately 500 m m . The inhibition type for both enzyme activities was fully competitive, the inhibition constants (Ki) being 65 and 285 mM for pectin lyase and endo-pectin lyase respectively. Glycerol also inhibited pectin lyases from the fungi Monilinia laxa, Monilinia fructigena, Alternaria alternata and Drechslera halodes. The possible inhibitory effect of other polyols and sugars on pectin lyase of B. cinerea was investigated. Mannitol and inositol were inhibitory at 0.5 m m and erythritol and arabitol at higher concentrations. The sugars investigated, trehalose, xylose, mannose, glucose and galactose were not inhibitory at any concentration up to 2 m m .

The Ability of a Novel Strain Scheffersomyces (Syn. Candida) shehatae Isolated from Rotten Wood to Produce Arabitol

Abstract: Arabitol is a polyalcohol which has about 70% of the sweetness of sucrose and an energy density of 0.2 kcal/g. Similarly to xylitol, it can be used in the food and pharmaceutical industries as a natural sweetener, a texturing agent, a dental caries reducer, and a humectant. Biotechnological production of arabitol from sugars represents an interesting alternative to chemical production. The yeast Scheffersomyces shehatae strain 20BM-3 isolated from rotten wood was screened for its ability to produce arabitol from L-arabinose, glucose, and xylose. This isolate, cultured at 28°C and 150 rpm, secreted 4.03 ± 0.00 to 7.97 ± 0.67 g/l of arabitol from 17-30 g/l of L-arabinose assimilated from a medium containing 20-80 g/l of this pentose with yields of 0.24 ± 0.00 to 0.36 ± 0.02 g/g. An optimization study demonstrated that pH 4.0, 32°C, and a shaking frequency of 150 rpm were the optimum conditions for arabitol production by the investigated strain. Under these conditions, strain 20BM-3 produced 6.2 ± 0.17 g/l of arabitol from 17.5 g/l of arabinose after 4 days with a yield of 0.35 ± 0.01 g/g. This strain also produced arabitol from glucose, giving much lower yields, but did not produce it from xylose. The new strain can be successfully used for arabitol production from abundantly available sugars found in plant biomass.

Adaptation of Flammulina velutipes to Hypothermia in Natural Environments: The Role of Lipids and Carbohydrates

Abstract: The role of lipids and carbohydrates in the adaptation of Flammulina velutipes to hypothermia (5 to −5°C) in natural environments has been studied for the first time. The main changes are were found to occur in membrane lipids: the levels of sterols and glycolipids decreased, and the proportion of phospholipids with a high degree of nonsaturation (2.2) increased, which was due to predominance of two fatty acids, linoleic (35% of the total) and linolenic (50%). Phosphatidylcholine became the major phospholipid. Under hypothermic conditions, glycerol, known to have antifreeze properties, accumulated in the cell cytosol along with arabitol and trehalose. The significance of this biochemical strategy in the resistance of the fungus to temperatures below zero (i.e., to cryobiotic conditions) is discussed.

Carbohydrate Spectrum of Extremophilic Yeasts Yarrowia lipolytica under pH Stress

Abstract: Alterations in the concentrations of cell cytosol carbohydrates of polyextremophilic yeasts Yarrowia lipolytica under stresses of diverse nature were observed. Under pH stress, mannitol was the main storage carbohydrate (up to 89% of the total cytosol carbohydrates), while arabitol, glucose, and inositol were present in insignificant amounts (3 to 6%). Experiments with inhibition of de novo mannitol synthesis by bis(p-nitrophenyl) disulfide revealed that the cytoprotective effect of mannitol was most noticeable in the cells grown under acidic conditions (pH 4.0), while the role of catalase and superoxide dismutase, the enzymes of the first line of antioxidant protection, increased under alkaline conditions (pH 9.0). The constitutively high mannitol content in Y. lipolytica cells was hypothesized to be a part of the core mechanism of stress resistance in this yeast species.

Coinduction of α-L-arabinofuranosidase and α-D-galactosidase formation in Trichoderma reesei RUT C-30.

Abstract: Formation of α-L-arabinosidase can be induced in Trichoderma reesei by growing the fungus on L-arabinose or dulcitol, and by adding L-arabinose, L-arabitol, D-galactose, or dulcitol ot non-growing mycelia. The same conditions also stimulated the formation of α-D-galactosidase, but not that of various other enzymes involved in hemicellulose degradation. The optimal inducer concentration with all compounds was 4 mM for both enzymes. Using L-arabinose and D-galactose, the induction efficiency was highest at pH 6.5, whereas induction by arabitol and dulcitol was more efficient at low pH (2.5). The addition of 50 mM glucose did not repress α-L-arabinosidase or α-D-galactosidase formation. These findings suggest coregulation of two hemicellulose side-chain cleaving enzymes in T. reesei.