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Chryssavgi Gardeli, Maria Athenaki, Evangelos Xenopoulos, Athanasios Mallouchos, Apostolis A Koutinas, George Aggelis, Seraphim Papanikolaou
AIMS: To study and characterize the lipids produced by Mortierella (Umbelopsis) isabellina, during its growth on mixtures of glucose and xylose. METHODS AND RESULTS: Glucose and xylose were utilized as carbon sources, solely or in blends, under nitrogen limited conditions, in batch-flask trials (initial sugars at 80 g l(-1) ). Significant lipid production (maximum lipid 17.8 g l(-1) ; lipid in DCW 61.0% w/w; lipid on glucose consumed 0.23 g g(-1) ) occurred on glucose employed solely, while glucose concentration in the growth medium was conversely correlated with lipid accumulation...
September 16, 2017: Journal of Applied Microbiology
Rahul J Hegde, Janhavi B Thakkar
AIM: This study aimed to compare and evaluate the changes in the salivary flow rate, pH, and buffering capacity before and after chewing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and xylitol-containing chewing gums in children. MATERIALS AND METHODS: Sixty children aged between 8 and 12 years were selected for the study. They were randomly divided into Group 1 (CPP-ACP chewing gum) and Group 2 (xylitol-containing chewing gum) comprising thirty children each...
October 2017: Journal of the Indian Society of Pedodontics and Preventive Dentistry
Xin Zeng, Junjie Zhao, Xusheng Chen, Zhonggui Mao, Wenyun Miao
The simultaneous consumption of glucose and glycerol led to remarkably higher productivity of both biomass and ε-poly-L-lysine (ε-PL), which was of great significance in industrial microbial fermentation. To further understand the superior fermentation performances, transcriptional analysis and exogenous substrates addition were carried out to study the simultaneous utilization of glucose and glycerol by Streptomyces albulus M-Z18. Transcriptome analysis revealed that there was no mutual transcriptional suppression between the utilization of glucose and glycerol, which was quite different from typical "glucose effect"...
September 13, 2017: Bioprocess and Biosystems Engineering
Hyoju Kim, Hyun-Soo Lee, Haeseong Park, Dae-Hee Lee, Eckhard Boles, Donghwa Chung, Yong-Cheol Park
Inefficient transport of xylose into Saccharomyces cerevisiae is a major hurdle for production of xylitol, a natural sweetener with five carbons. To facilitate the xylose transport and hence increase xylose conversion to xylitol, the araE gene encoding an arabinose:H(+) symporter (AraE) from Bacillus subtilis and the XYL1 gene from Scheffersomyces stipitis were expressed in Saccharomyces cerevisiae EBY.VW4000, a hxt null mutant. The resulting strain of EXHA exhibited 4.1 fold increases in xylose consumption rate and xylitol productivity, relative to the control strain without AraE...
December 2017: Enzyme and Microbial Technology
Shengbo Hou, Hualiang Feng, Jiaoqi Gao, Yimin Li, Wenjie Yuan, Fengwu Bai
Kluyveromyces marxianus, as unconventional yeast, attracts more and more attention in the biofuel fermentation. Although this sort of yeasts can ferment pentose sugars, the fermentation capacity differs largely. Xylose and arabinose fermentation by three K. marxianus strains (K. m 9009, K. m 1911 and K. m 1727) were compared at different temperatures. The results showed that the fermentation performance of the three strains had significant difference under different fermentation temperatures. Especially, the sugar consumption rate and alcohol yield of K...
June 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
Raquel M Cadete, Carlos A Rosa
Yeasts of the Spathaspora clade have the ability to convert d-xylose to ethanol and/or xylitol. This is an important trait, as these yeasts may be used to produce bioethanol from lignocellulosic biomass, or as a source of new d-xylose metabolism genes for recombinant industrial strains of Saccharomyces cerevisiae. The core group of the genus Spathaspora has 22 species, both formally described and not yet described. Other species, such as Sp. allomyrinae, Candida alai, C. insectamans, C. lyxosophila, C. sake, Sp...
September 11, 2017: Yeast
Gisele Marta Martins, Daniela Alonso Bocchini-Martins, Carolina Bezzerra-Bussoli, Fernando Carlos Pagnocca, Maurício Boscolo, Diego Alves Monteiro, Roberto da Silva, Eleni Gomes
For the implementation of cellulosic ethanol technology, the maximum use of lignocellulosic materials is important to increase efficiency and to reduce costs. In this context, appropriate use of the pentose released by hemicellulose hydrolysis could improve de economic viability of this process. Since the Saccharomyces cerevisiae is unable to ferment the pentose, the search for pentose-fermenting microorganisms could be an alternative. In this work, the isolation of yeast strains from decaying vegetal materials, flowers, fruits and insects and their application for assimilation and alcoholic fermentation of xylose were carried out...
August 26, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
Dana Colpa, Nikola Loncar, Mareike Schmidt, Marco Fraaije
In this work we prepared a set of bifunctional oxidase-peroxidases by fusing four distinct oxidases to a peroxidase. While such fusion enzymes have not been observed in nature, they could be expressed and purified with good yields. Characterization revealed that the artificial enzymes retained the capability to bind the two required cofactors and were catalytically active as oxidase and peroxidase. The peroxidase fusions of alditol oxidase and chitooligosaccharide oxidase could be used for selective detection of xylitol and cellobiose with a detection limit in the low µM range...
September 8, 2017: Chembiochem: a European Journal of Chemical Biology
Vera Novy, Ruifei Wang, Johan O Westman, Carl Johan Franzén, Bernd Nidetzky
BACKGROUND: The most advanced strains of xylose-fermenting Saccharomyces cerevisiae still utilize xylose far less efficiently than glucose, despite the extensive metabolic and evolutionary engineering applied in their development. Systematic comparison of strains across literature is difficult due to widely varying conditions used for determining key physiological parameters. Here, we evaluate an industrial and a laboratory S. cerevisiae strain, which has the assimilation of xylose via xylitol in common, but differ fundamentally in the history of their adaptive laboratory evolution development, and in the cofactor specificity of the xylose reductase (XR) and xylitol dehydrogenase (XDH)...
2017: Biotechnology for Biofuels
Yeon-Hum Yun, Chang-Moon Lee, Youn-Sop Kim, Soon-Do Yoon
This paper reports on a method of preparing chitosan-based films to which sulfosuccinic acid (SSA) is added for crosslinking agent with/without UV curing treatment and applications of a coating materials for foods. The physical, thermal, and optical properties of the UV cured chitosan-based films are investigated including their tensile strength (TS), elongation at break (%E), degree of swelling (DS), solubility (S), and water vapor absorption as well as their biodegradability in soil and applicability of the coating on a fruit...
October 2017: Food Research International
Thomas Thomik, Ilka Wittig, Jun-Yong Choe, Eckhard Boles, Mislav Oreb
Efficient substrate utilization is the first and most important prerequisite for economically viable production of biofuels and chemicals by microbial cell factories. However, production rates and yields are often compromised by low transport rates of substrates across biological membranes and their diversion to competing pathways. This is especially true when common chassis organisms are engineered to utilize nonphysiological feedstocks. Here, we addressed this problem by constructing an artificial complex between an endogenous sugar transporter and a heterologous xylose isomerase in Saccharomyces cerevisiae...
September 4, 2017: Nature Chemical Biology
Ji Eun Bae, In Jung Kim, Ki Hyun Nam
Glucose isomerase (GI) is an intramolecular oxidoreductase that interconverts aldoses and ketoses. These characteristics are widely used in the food, detergent, and pharmaceutical industries. In order to obtain an efficient GI, identification of novel GI genes and substrate binding/inhibition have been studied. Xylitol is a well-known inhibitor of GI. In Streptomyces rubiginosus, two crystal structures have been reported for GI in complex with xylitol inhibitor. However, a structural comparison showed that xylitol can have variable conformation at the substrate binding site, e...
August 30, 2017: Biochemical and Biophysical Research Communications
Qi Han, Mark A Eiteman
Escherichia coli expressing NAD-dependent xylitol-4-dehydrogenase (XDH) from Pantoea ananatis and growing on glucose or glycerol converts xylitol to the rare sugar l-xylulose. Although blocking potential l-xylulose consumption (l-xylulosekinase, lyxK) or co-expression of the glycerol facilitator (glpF) did not significantly affect l-xylulose formation, co-expressing XDH with water-forming NADH oxidase (NOX) from Streptococcus pneumoniae increased l-xylulose formation in shake flasks when glycerol was the carbon source...
November 2017: Enzyme and Microbial Technology
Parind M Desai, Rachael C Hogan, David Brancazio, Vibha Puri, Keith D Jensen, Jung-Hoon Chun, Allan S Myerson, Bernhardt L Trout
This study provides a framework for robust tablet development using an integrated hot-melt extrusion-injection molding (IM) continuous manufacturing platform. Griseofulvin, maltodextrin, xylitol and lactose were employed as drug, carrier, plasticizer and reinforcing agent respectively. A pre-blended drug-excipient mixture was fed from a loss-in-weight feeder to a twin-screw extruder. The extrudate was subsequently injected directly into the integrated IM unit and molded into tablets. Tablets were stored in different storage conditions up to 20 weeks to monitor physical stability and were evaluated by polarized light microscopy, DSC, SEM, XRD and dissolution analysis...
August 24, 2017: International Journal of Pharmaceutics
Peiyan Shen, Glenn D Walker, Yi Yuan, Coralie Reynolds, Eric C Reynolds
Sugar-free chewing gum containing polyols has been demonstrated to reduce caries experience in randomised controlled clinical trials. A range of polyols (mannitol, sorbitol, xylitol and maltitol) can be found in sugar-free gums and it has been claimed that they can facilitate calcium uptake into enamel subsurface lesions promoting remineralisation. OBJECTIVES: The aim of this study was to compare the effect of polyols on remineralisation of enamel subsurface lesions in vitro by artificial saliva (AS) and by AS containing the salivary biomimetic casein phosphopeptide amorphous calcium phosphate (CPP-ACP)...
August 21, 2017: Journal of Dentistry
Yoshiharu Suzuki
I examined the polyamorphic behavior of glassy dilute aqueous solutions of polyols (ethylene glycol, glycerol, meso-erythritol, xylitol, and D-sorbitol) under pressure at low temperatures. Although the volume change of the glassy aqueous solution varied continuously against pressure, the rate of the volume change appeared to vary discontinuously at the onset pressure of the gradual polyamorphic transition. It is thought that low-density liquid-like solvent water and high-density liquid-like solvent water coexist during the transition...
August 14, 2017: Journal of Chemical Physics
R M Cadete, M A Melo-Cheab, K J Dussán, R C L B Rodrigues, S S da Silva, F C O Gomes, C A Rosa
AIMS: This study aimed to evaluate new d-xylose-fermenting yeasts from Brazilian ecosystems for the production of second-generation ethanol. METHODS AND RESULTS: d-xylose-fermenting yeasts isolated from rotting wood and wood-boring insects were identified as the species Scheffersomyces parashehatae, Sc. illinoinensis, Spathaspora arborariae, and Wickerhamomyces rabaulensis. Among the yeasts tested, those of Scheffersomyces parashehatae exhibited the highest ethanol production when cultivated on complex medium (Yp/s(et) = 0...
August 11, 2017: Journal of Applied Microbiology
(no author information available yet)
No abstract text is available yet for this article.
August 11, 2017: British Dental Journal
Stephan Höhlein, Andreas König-Haagen, Dieter Brüggemann
The application range of existing real scale mobile thermal storage units with phase change materials (PCM) is restricted by the low phase change temperature of 58 ∘ C for sodium acetate trihydrate, which is a commonly used storage material. Therefore, only low temperature heat sinks like swimming pools or greenhouses can be supplied. With increasing phase change temperatures, more applications like domestic heating or industrial process heat could be operated. The aim of this study is to find alternative PCM with phase change temperatures between 90 and 150 ∘ C ...
April 24, 2017: Materials
Melih N Korkmaz, Sennur C Ozdemir, Ataç Uzel
Xylanases constitutes one the most important enzymes with diverse applications in different industries such as bioethanol production, animal feedstock production, production of xylo-oligosaccharides, baking industry, paper and pulp industry, xylitol production, fruit juice, and beer finishing, degumming, and agriculture. Currently, industrial xylanases are mainly produced by Aspergillus and Trichoderma members. Since the marine environments are less studied compared to terrestrial environments and harbors great microbial diversity we aimed to investigate the xylanase production of 88 marine-derived filamentous fungal strains...
July 31, 2017: Journal of Basic Microbiology
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