Showing papers on "Arabitol published in 2019"

Isolation, identification and screening of yeasts towards their ability to assimilate biodiesel-derived crude glycerol: microbial production of polyols, endopolysaccharides and lipid.

Abstract: Aims To assess the ability of various newly isolated or belonging in official collections yeast strains to convert biodiesel-derived glycerol (Gly) into added-value compounds. Methods and results Ten newly isolated yeast strains belonging to Debaryomyces sp., Naganishia uzbekistanensis, Rhodotorula sp. and Yarrowia lipolytica, isolated from fishes, metabolized Gly under nitrogen limitation. The aim of the study was to identify potential newly isolated microbial candidates that could produce single-cell oil (SCO), endopolysaccharides and polyols when these micro-organisms were grown on biodiesel-derived Gly. As controls producing SCO and endopolysaccharides were the strains Rhodotorula glutinis NRRL YB-252 and Cryptococcus curvatus NRRL Y-1511. At initial Gly (Gly0 ) ≈40 g l-1 , most strains presented remarkable dry cell weight (DCW) production, whereas Y. lipolytica and Debaryomyces sp. produced non-negligible quantities of mannitol and arabitol (Ara). Five strains were further cultivated at increasing Gly0 concentrations. Rhodotorula glutinis NRRL YB-252 produced 7·2 g l-1 of lipid (lipid in DCW value ≈38% w/w), whereas Debaryomyces sp. FMCC Y69 in batch-bioreactor experiment with Gly0 ≈80 g l-1 , produced 30-33 g l-1 of DCW and ~30 g l-1 of Ara. At shake-flasks with Gly0 ≈125 g l-1 , Ara of ~48 g l-1 (conversion yield of polyol on Gly consumed ≈0·62 g g-1 ) was achieved. Cellular lipids of all yeasts contained in variable concentrations oleic, palmitic, stearic and linoleic acids. Conclusions Newly isolated, food-derived and non-previously studied yeast isolates converted biodiesel-derived Gly into several added-value metabolites. Significance and impact of the study Alternative ways of crude Gly valorization through yeast fermentations were provided and added-value compounds were synthesized.

A pH shift induces high-titer liamocin production in Aureobasidium pullulans

Abstract: Liamocins are biosurfactants produced by the fungus Aureobasidium pullulans. A. pullulans belongs to the black yeasts and is known for its ability to produce pullulan and melanin. However, the production of liamocins has not been investigated intensively. Initially, HPLC methods for the quantification of liamocin and the identification of liamocin congeners were established. Eleven congeners could be detected, differing in the polyol head groups arabitol or mannitol. In addition, headless molecules, so-called exophilins, were also identified. The HPLC method reported here allows quick and reliable quantification of all identified congeners, an often-overlooked prerequisite for the investigation of valuable product formation. Liamocin synthesis was optimized during cultivation in lab-scale fermenters. While the pH can be kept constant, the best strategy for liamocin synthesis consists of a growth phase at neutral pH and a subsequent production phase induced by a manual pH shift to pH 3.5. Finally, combining increased nitrogen availability with a pulsed fed-batch fermentation, cell growth, and liamocin titers could be enhanced. Here, the maximal titers of above 10 g/L that were reached are the highest reported to date for liamocin synthesis using A. pullulans in lab-scale fermenters.

Polyol dehydrogenases: intermediate role in the bioconversion of rare sugars and alcohols

Abstract: Polyol dehydrogenases (PDHs) play a pivotal role in the biotransformation between rare sugar and alcohol. Among these PDHs, mannitol 2-dehydrogenase (MDH, EC 1.1.1.67), galactitol 2-dehydrogenase (GDH, EC 1.1.1.16), ribitol 2-dehydrogenase (RDH, EC 1.1.1.56), xylitol 4-dehydrogenase (XDH, EC 1.1.1.14), and arabitol 2-dehydrogenase (ArDH, EC 1.1.1.12) are the most studied. MDH can catalyze the transformation between D-fructose and mannitol as well as the transformation between D-arabitol and D-xylulose. In addition to MDH, the other PDHs including RDH, GDH, ArDH, and XDH are also important tools for the production of rare sugars including D-tagatose, allitol, D-xylulose, and L-xylulose. Concerning the intermediate function of PDH in the linkage of rare sugar and sugar alcohols, this review attempts to conclude their catalytic properties and potential applications.

Characterization of D-Arabitol as Newly Discovered Carbon Source of Bacillus methanolicus.

Abstract: Bacillus methanolicus is a Gram-positive, thermophilic, methanol-utilizing bacterium. As a facultative methylotroph, B. methanolicus is also known to utilize D-mannitol, D-glucose and, as recently discovered, sugar alcohol D-arabitol. While metabolic pathways for utilization of methanol, mannitol and glucose are known, catabolism of arabitol has not yet been characterized in B. methanolicus. In this work we present the elucidation of this hitherto uncharted pathway. In order to confirm our predictions regarding genes coding for arabitol utilization, we performed differential gene expression analysis of B. methanolicus MGA3 cells grown on arabitol as compared to mannitol via transcriptome sequencing (RNA-seq). We identified a gene cluster comprising eight genes that was up-regulated during growth with arabitol as a sole carbon source. The RNA-seq results were subsequently confirmed via qRT-PCR experiments. The transcriptional organization of the gene cluster identified via RNA-seq was analyzed and it was shown that the arabitol utilization genes are co-transcribed in an operon that spans from BMMGA3_RS07325 to BMMGA3_RS07365. Since gene deletion studies are currently not possible in B. methanolicus, two complementation experiments were performed in an arabitol negative Corynebacterium glutamicum strain using the four genes discovered via RNA-seq analysis as coding for a putative PTS for arabitol uptake (BMMGA3_RS07330, BMMGA3_RS07335, and BMMGA3_RS07340 renamed to atlABC) and a putative arabitol phosphate dehydrogenase (BMMGA3_RS07345 renamed to atlD). C. glutamicum is a natural D-arabitol utilizer that requires arabitol dehydrogenase MtlD for arabitol catabolism. The C. glutamicum mtlD deletion mutant was chosen for complementation experiments. Heterologous expression of atlABCD as well as the arabitol phosphate dehydrogenase gene atlD from B. methanolicus alone restored growth of the C. glutamicum ΔmtlD mutant with arabitol. Furthermore, D-arabitol phosphate dehydrogenase activities could be detected in crude extracts of B. methanolicus and these were higher in arabitol-grown cells than in methanol- or mannitol-grown cells. Thus, B. methanolicus possesses an arabitol inducible operon encoding, amongst others, a putative PTS system and an arabitol phosphate dehydrogenase for uptake and activation of arabitol as growth substrate.

Screening of new yeast Pichia manchurica for arabitol production

Abstract: Arabitol has several applications in food and pharmaceutical industries as a natural sweetener, dental caries inhibitor, and texturing agent. Newly isolated yeast strains from seawater, sugarcane plantation soil samples, and Zygosaccharomyces rouxii 2635 from MTCC were tested for arabitol production. The yield of arabitol was found to be higher in seawater isolate (24.6 g L-1 ) compared to two soil isolates (22.5 g L-1 ) and Z. rouxii (19.4 g L-1 ). Based on ITS 26S rDNA sequence analysis, the seawater isolate was identified as Pichia manchurica. In the present study, the effect of different substrates, trace elements, nitrogen sources, pH, and temperature on arabitol production was examined. Three different carbon sources viz. glucose, arabinose, and galactose were studied. Glucose was determined to be the best substrate for arabitol production (27.6 g L-1 ) followed by arabinose (13.7 g L-1 ) and galactose (7.7 g L-1 ). Maximum production of arabitol was observed at pH 6.0 (34.7 g L-1 ). In addition, arabitol production was high (35.7 g L-1 ) at temperature of 30 °C. Among the different concentrations of ammonium sulfate tested (3, 4.5, 6, 7.5, and 9 g L-1 ) concentration of 6 g L-1 resulted in higher arabitol Individual metal ions had no effect on arabitol production by this strain as compared to control. Results obtained in this study identify ways for improved arabitol production with natural isolates using microbial processes.

Method for simultaneously detecting 22 sugars, sugar alcohol and alcohol in fruit juice

Abstract: The invention discloses a method for simultaneously detecting 22 sugars, sugar alcohol and alcohol in fruit juice, and belongs to the field of analytical chemistry. The method adopts an integral impulse ampere-ion chromatography to research experiment factors affecting component separation via a processing method before optimization; and the method for simultaneously detecting the 22 sugars, the sugar alcohol and the alcohol (2,3-butanediol, propylene glycol, methyl alcohol, glycerin, erythritol, xylitol, rhamnose, arabitol, sorbitol, trehalose, galactitol, mannitol, 2-deoxidized-D-glucose, arabinose, melibiose, glucose, galactose, fructose, ribose, saccharose, raffinose and maltose) at a time is built. The technical difficulty of accurately analyzing the plurality of components, sugars, sugar alcohol and alcohol, in the fruit juice is solved; the method is fast, accurate and sensitive, achieves simultaneous analysis of the plurality of categories and the plurality of components, and makes an important contribution to component detection of the fruit juice.

Method for simultaneous rapid detection of various sugars, sugar alcohols and alcohols in beer

Abstract: The invention discloses a method for simultaneous rapid detection of various sugars, sugar alcohols and alcohols in beer, belonging to the technical field of analytical chemistry. In the method provided by the invention, an integrated pulsed amperometric-ion chromatography is used, by optimization of a pretreatment detection method, experimental factors influencing separation of constituents are researched, and a method for simultaneously detecting 23 types of sugars, sugar alcohols and alcohols (2, 3-butanediol, ethyl alcohol, methanol, glycerin, erythritol, xylitol, fucose, arabitol, sorbitol, trehalose, ribovitol, mannitol, 2-DNA-D-glucose, mannose, melibiose, glucose, maltitol, fructose, lactose, ribose, sucrose, raffinose and maltitol ) in the beer is built one time. Thus, a technicalproblem of accurate analysis on multiple constituents including the sugars, the sugar alcohols and the alcohols in the beer is solved, the method provided by the invention is rapid, accurate and sensitive, realizes simultaneous analysis of multiple types and multiple constituents, and makes an important contribution to detection of beer constituents.

Preparation method of arabitol

Abstract: The invention discloses a preparation method of arabitol. The method comprises the steps as follows: performing a nanofiltration operation of 500-molecular weight on an edible fungus extracting solution; collecting a fraction with the molecular weight less than 500; performing a reverse osmosis membrane filtration operation on the extracting solution with the molecular weight less than 500; concentrating feed liquid until the soluble solid content reaches 40-50%, adding absolute ethyl alcohol for crystallization, and performing suction filtration to obtain crude crystals; mixing the crude crystals with absolute ethyl alcohol at the weight ratio of 1:20 and heating until the mixture is dissolved, standing still, naturally cooling to be recrystallized, performing suction filtered, and dryingto obtain high-purity sugar alcohol crystals. The preparation method of the arabitol provided by the invention is simple to operate, and the prepared arabitol is high in purity.