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.

l-Arabinose metabolism in Candida arabinofermentans PYCC 5603T and Pichia guilliermondii PYCC 3012: influence of sugar and oxygen on product formation

Abstract: l-Arabinose utilization by the yeasts Candida arabinofermentans PYCC 5603T and Pichia guilliermondii PYCC 3012 was investigated in aerobic batch cultures and compared, under similar conditions, to d-glucose and d-xylose metabolism. At high aeration levels, only biomass was formed from all the three sugars. When oxygen became limited, ethanol was produced from d-glucose, demonstrating a fermentative pathway in these yeasts. However, pentoses were essentially respired and, under oxygen limitation, the respective polyols accumulated—arabitol from l-arabinose and xylitol from d-xylose. Different l-arabinose concentrations and oxygen conditions were tested to better understand l-arabinose metabolism. P. guilliermondii PYCC 3012 excreted considerably more arabitol from l-arabinose (and also xylitol from d-xylose) than C. arabinofermentans PYCC 5603T. In contrast to the latter, P. guilliermondii PYCC 3012 did not produce any traces of ethanol in complex l-arabinose (80 g/l) medium under oxygen-limited conditions. Neither sustained growth nor active metabolism was observed under anaerobiosis. This study demonstrates, for the first time, the oxygen dependence of metabolite and product formation in l-arabinose-assimilating yeasts.

Metabolic study of the adaptation of the yeast Candida guilliermondii to sugarcane bagasse hydrolysate.

Abstract: Batch xylitol production from concentrated sugarcane bagasse hydrolysate by Candida guilliermondii was performed by progressively adapting the cells to the medium. Samples were analyzed to monitor sugar and acetic acid consumption, xylitol, arabitol, ethanol, and carbon dioxide production, as well as cell growth. Both xylitol yield and volumetric productivity remarkably increased with the number of adaptations, demonstrating that the more adapted the cells, the better the capacity of the yeast to reduce xylose to xylitol in hemicellulose hydrolysates. Substrate and product concentrations were used in carbon material balances to study in which way the different carbon sources were utilized by this yeast under microaerobic conditions, as well as to shed light on the effect of the progressive adaptation to the medium on its fermentative activity. Such a theoretical means allowed estimation for the first time of the relative contribution of each medium component to the formation of the main products of this fermentation system.

Carbohydrate Storage in the Entomopathogenic Fungus Beauveria bassiana.

Abstract: The entomopathogenic fungus Beauveria bassiana was grown in 1% (wt/vol) gelatin-liquid media singly supplemented with a monosaccharide (glucose or fructose), a disaccharide (maltose or trehalose), a polyol (glycerol, mannitol, or sorbitol), or the amino sugar N-acetyl-d-glucosamine The relative contributions of the carbohydrate, protein, and water contents in the fungal biomass were determined Carbohydrates composed 18 to 42% of the mycelial dry weight, and this value was lowest in unsupplemented medium and highest in medium supplemented with glucose, glycerol, or trehalose Biomass production was highest in liquid cultures supplemented with trehalose When liquid cultures were grown in medium supplemented with 0 to 1% (wt/vol) glucose, trehalose, or N-acetyl-d-glucosamine, there was an increase in the biomass production and the contribution of carbohydrate to mycelial dry weight Regardless of the glucose concentration in the culture, water content of the mycelia remained about 775% (wt/wt) Mycelial storage carbohydrates were determined by capillary gas chromatography In gelatin-liquid medium supplemented with 1% (wt/vol) glucose, B bassiana stored glycogen (120%, wt/dry wt) and the polyols mannitol (22%), erythritol (16%), glycerol (04%), and arabitol (01%) Without glucose, B bassiana stored glycogen (54%), mannitol (08%), glycerol (06%), and erythritol (06%) but not arabitol To our knowledge, this is the first report of carbohydrate storage in an entomopathogenic fungus, and the results are discussed in relation to other fungi and the potential implications to commercial formulation and insect-fungus interactions

Accumulation and partial re-consumption of polyols during citric acid fermentation by Aspergillus niger

Abstract: Quantitative balances have been made for sugar and oxygen uptake rates during citric acid accumulation by Aspergillus niger: during the first phase of citric acid accumulation (up to 130 h) more sugar is taken up than the production of biomass, CO2 and citric acid account for. In contrast, during later phases of fermentation more citric acid, CO2 and biomass are formed than sugar uptake would theoretically allow. A similar pattern is obtained for oxygen uptake, where less uptake occurs during the early phase of fermentation than needed for complete balance, and the reverse is observed during the late stage of fermentation. It could subsequently be shown that this is caused by the intermediate accumulation and partial re-consumption of a number of polyhydric alcohols (glycerol, arabitol, erythritol and mannitol) during citric acid fermentation.

Carbohydrate metabolism in the fungus dendryphiella salina

Abstract: Summary When Dendryphiella salina was grown on non-saline media, mannitol and arabitol were the only polyols present in the mycelium. In media made up with sea-water or salinized by high concentrations of salts of potassium, sodium and magnesium, glycerol was also present. When mycelium grown in sea-water was transferred to distilled water, the glycerol content dropped very rapidly to zero. The amounts of mannitol and arabitol also declined. Transfer of similarly grown mycelium to sea-water alone reduced the rate of decline of glycerol, caused little change in the amount of mannitol and induced a rise in that of arabitol. These observations help to explain the absence of glycerol in mycelium in previous studies. The concentration (mol l−1) of solutes within mycelium were determined after 48 h growth in the presence of either sodium chloride, magnesium chloride, sodium sulphate, inositol or betaine at either 0.4 or 0.8 osmol kg−1water. There was a very similar total polyol concentration at each osmolality in the saline media irrespective of the salt, even though there could be different concentrations of individual polyols. With inositol in the medium, the same held if the endogenous concentration of that compound was included in the total. The same did not hold for betaine, in which medium growth was poor. The total polyol concentration increased in all cases with the osmolality of the medium. With respect to the total concentration of solutes present (excluding data for mycelium grown in betaine), polyols were 19 to 33 % of the total, α-amino nitrogen, 11 to 34% and organic acids, 0 to 8 %. These percentages take into account data obtained by 24Na-flux studies, which indicate that, in media containing sodium salts, much of the mycelial content of the cation may be located in the wall.