Showing papers on "Arabitol published in 2017"

Polyols, not sugars, determine the structural diversity of anti-streptococcal liamocins produced by Aureobasidium pullulans strain NRRL 50380

Abstract: Liamocins are polyol lipids produced by the fungus Aureobasidium pullulans, and have selective antibacterial activity against Streptococcus species. Liamocins produced by A. pullulans strain NRRL 50380 on sucrose medium have a d-mannitol head group ester-linked to 3,5-dihydroxydecanoate acyl chains, three or four of which are joined together by 1,5-polyester bonds (liamocins Man-A1 and Man-B1), and similar 3'-O-acetylated analogs (Man-A2 and Man-B2). However, other types of liamocins are produced depending on the choice of strain and growth conditions. In the current study, growth on different polyols, but not sugars, resulted in considerable structural variation, including liamocins with d-galactitol (dulcitol), d-sorbitol (glucitol), d- and l-arabitol, d-xylitol, l-threitol and glycerol head groups. The head groups of liamocins produced on arabitol were shown to be entirely composed of d-arabitol. These liamocin variants were structurally characterized by NMR and MS, and tested for antibacterial activity. The new liamocin variants also had selective activity against Streptococcus. Liamocin structural variants are novel antibacterials against Streptococcus sp. that merit further investigation.

Erythritol production by Yarrowia lipolytica mutant strain M53 generated through atmospheric and room temperature plasma mutagenesis

Abstract: Mutants of Yarrowia lipolytica with high erythritol production were generated through an atmospheric and room temperature plasma (ARTP) mutation system. Among these mutants, Y. lipolytica M53 exhibited the highest erythritol yield. In a batch culture, M53 produced 64.8 g/L erythritol from 100 g/L glycerol. The yields of byproducts (e.g. mannitol, arabitol, and α-ketoglutaric acid) were low, and the mechanisms underlying these changes were examined by measuring enzyme activities in the pentose phosphate pathway. Up to 145.2 g/L erythritol was produced by M53 from 200 g/L of glycerol, and erythritol accumulation was promoted by 3.7 mg/L of Cu2+, 10.15 mg/L of Mn2+, and 30.37 g/L of NaCl. Fed-batch cultivation of M53 in a 5-L fermentor produced 169.3 g/L erythritol with low levels of byproducts within 168 h. This finding confirmed the potential of M53 as an erythritol producer on a commercial scale.

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.

The production of arabitol by a novel plant yeast isolate Candida parapsilosis 27RL-4

Abstract: Abstract Polyalcohol arabitol can be used in the food and pharmaceutical industries as a natural sweetener, a dental caries reducer, and texturing agent. Environmental samples were screened to isolate effective yeast producers of arabitol. The most promising isolate 27RL-4, obtained from raspberry leaves, was identified genetically and biochemically as Candida parapsilosis. It secreted 10.42– 10.72 g l-1 of product from 20 g l-1 of L-arabinose with a yield of 0.51 - 0.53 g g-1 at 28°C and a rotational speed of 150 rpm. Batch cultures showed that optimal pH value for arabitol production was 5.5. High yields and productivities of arabitol were obtained during incubation of the yeast at 200 rpm, or at 32°C, but the concentrations of the polyol did not exceed 10 g l-1. In modified medium, with reduced amounts of nitrogen compounds and pH 5.5-6.5, lower yeast biomass produced a similar concentration of arabitol, suggesting higher efficiency of yeast cells. This strain also produced arabitol from glucose, with much lower yields. The search for new strains able to successfully produce arabitol is important for allowing the utilization of sugars abundant in plant biomass.

Simultaneous quantification of carbohydrates and metabolites in multicomponent fermentation broths by means of high-performance thin-layer chromatography

Abstract: Quantification of carbohydrates and metabolites in fermentation processes can be considered as key factor in determining yield and productivity for a better understanding of the microbial behavior under different conditions. The main aim of the present study was to develop and set up analytical methods for detecting complex sugar and/or metabolite mixtures in fermentation broth based on high-performance thin-layer chromatography (HPTLC). HPTLC is a fast and accurate method of separating complex mixtures, based on planar development. The proposed methods involved the separations of a mixture of monosaccharides (glucose, xylose, arabinose, and rhamnose) deriving from delignification and hydrolysis of hazelnut shells and the corresponding sugar alcohols (xylitol, arabitol, and sorbitol) obtained by fermentations of Candida tropicalis spp., a yeast able to ferment aldoses to produce sugar alcohols. HPTLC methods were set up on simple chamber development and using instrumental techniques like overpressured lay...

Neutral lipid production by the yeast Debaryomyces hansenii NCYC102 under different stress conditions

Abstract: Oleaginous yeasts are very efficient in the accumulation of triacylglycerol, and are expected to be one of the most important feedstocks for the biofuel industry in the future. Lipid content can be enhanced through physiological stress or genetic manipulation. Debaryomyces hansenii NCYC102 was selected from three different yeast species (also including Yarrowia lipolytica NCYC476 and Cryptococcus curvatus NCYC2904) due to the highest neutral lipid content. The growth rate, osmolytes and neutral lipids were measured in cells grown under different concentrations (0, 0.8, 1.6 M) of NaCl. The maximum content of total osmolytes was found in 0.8 M NaCl YM medium. However, the highest level of glycerol was measured in 1.6 M NaCl grown cells. The main osmolytes identified by 1H NMR spectroscopy were glycerol, arabitol, glucose and trehalose. Debaryomyces. hansenii cells were grown in minimal medium with different carbon/nitrogen ratios using either glucose or glycerol as the sole carbon source along with ammonium sulphate as nitrogen source. Maximal neutral lipid production was observed in 48:0.5 glucose/ammonium sulphate ratio which achieved 1.4-fold increase compared with glycerol-based medium (8 glycerol: 0.25 ammonium sulphate). GC-MS analysis of the transesterified fatty acids showed that palmitic, oleic and stearic acids were the main fatty acids present, under normal and stress conditions (high salt and limited nitrogen source). Deletion of the GUT2 encoding for G3P dehydrogenase increased neutral lipid production up to a 1.4-fold compared to wild type strains. The mutant strains displayed slightly higher cell densities in medium with glucose when compared with wild type strains, while they failed to grow on glycerol as a sole carbon source. Collectively, these results indicate that D. hansenii is a good organism to produce biofuels as it has an intrinsic ability to accumulate neutral lipids and this can be further enhanced by genetic and metabolic engineering.

Arabitol and xylitol based flame retardants

Abstract: A flame retardant sugar-derived molecule, a process for forming a flame retardant sugar-derived molecule, and an article of manufacture comprising a flame retardant sugar-derived molecule are disclosed. The flame retardant sugar-derived molecule can be synthesized from arabitol, xylitol, arabic acid, or xylonic acid obtained from a bio-based source, and can have at least one phosphoryl or phosphonyl moiety. The process for forming the flame retardant sugar-derived molecule can include reacting arabitol, xylitol, arabic acid, or xylonic acid and a flame retardant phosphorus-based molecule to form the flame retardant sugar-derived molecule.