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Characterisation of a catalytic triad and reaction selectivity in the dual mechanism of the catalyse hydride transfer in xylitol phosphate dehydrogenase

Razali SA, Shamsir MS

J Mol Graph Model, 2020 06;97:107548.
PMID: 32023508 DOI: 10.1016/j.jmgm.2020.107548

Xylitol is a high-value low-calorie sweetener used as sugar substitute in food and pharmaceutical industry. Xylitol phosphate dehydrogenase (XPDH) catalyses the conversion of d-xylulose 5-phosphate (XU5P) and d-ribulose 5-phosphate (RU5P) to xylitol and ribitol respectively in the presence of nicotinamide adenine dinucleotide hydride (NADH). Although these enzymes have been shown to produce xylitol and ribitol, there is an incomplete understanding of the mechanism of the catalytic events of these reactions and the detailed mechanism has yet to be elucidated. The main goal of this work is to analyse the conformational changes of XPDH-bound ligands such as zinc, NADH, XU5P, and RU5P to elucidate the key amino acids involved in the substrate binding. In silico modelling, comparative molecular dynamics simulations, interaction analysis and conformational study were carried out on three XPDH enzymes of the Medium-chain dehydrogenase (MDR) family in order to elucidate the atomistic details of conformational transition, especially on the open and closed state of XPDH. The analysis also revealed the possible mechanism of substrate specificity that are responsible in the catalyse hydride transfer are the residues His58 and Ser39 which would act as the proton donor for reduction of XU5P and RU5P respectively. The structural comparison and MD simulations displayed a significant difference in the conformational dynamics of the catalytic and coenzyme loops between Apo and XPDH-complexes and highlight the contribution of newly found triad residues. This study would assist future mutagenesis study and enzyme modification work to increase the catalysis efficiency of xylitol production in the industry.

Matched MeSH terms: Xylitol*
Effects of electrospun nanofiber fabrications on immobilization of recombinant Escherichia coli for production of xylitol from glucose

Mohamad Sukri N, Abdul Manas NH, Jaafar NR, A Rahman R, Abdul Murad AM, Md Illias R

Enzyme Microb Technol, 2024 Jan;172:110350.
PMID: 37948908 DOI: 10.1016/j.enzmictec.2023.110350

A suitable nanofiber sheet was formulated and developed based on its efficacy in the immobilization of recombinant Escherichia coli (E. coli) to enhance xylitol production. The effects of different types of nanofibers and solvents on cell immobilization and xylitol production were studied. The most applicable nanofiber membrane was selected via preliminary screening of four types of nanofiber membrane, followed by the selection of six different solvents. Polyvinylidene fluoride (PVDF) nanofiber sheet synthesized using dimethylformamide (DMF) solvent was found to be the most suitable carrier for immobilization and xylitol production. The thin, beaded PVDF (DMF) nanofibers were more favourable for microbial adhesion, with the number of immobilized cells as high as 96 × 106 ± 3.0 cfu/ml. The attraction force between positively charged PVDF nanofibers and the negatively charged E. coli indicates that the electrostatic interaction plays a significant role in cell adsorption. The use of DMF has also produced PVDF nanofibers biocatalyst capable of synthesizing the highest xylitol concentration (2.168 g/l) and productivity (0.090 g/l/h) and 55-69% reduction in cell lysis compared with DMSO solvent and free cells. This finding suggests that recombinant E. coli immobilized on nanofibers shows great potential as a whole-cell biocatalyst for xylitol production.

Matched MeSH terms: Xylitol/metabolism
Fulltext Exploring pineapple peel hydrolysate as a sustainable carbon source for xylitol production

Nasoha NZ, Luthfi AAI, Roslan MF, Hariz HB, Bukhari NA, Manaf SFA

Sci Rep, 2023 Nov 07;13(1):19284.
PMID: 37935748 DOI: 10.1038/s41598-023-46061-8

This study explores utilizing pineapple peel (PP) hydrolysate as a promising carbon source for xylitol production, covering scopes from the pre-treatment to the fermentation process. The highest xylose concentration achieved was around 20 g/L via mild acid hydrolysis (5% nitric acid, 105 °C, 20-min residence time) with a solid loading of 10%. Two sets fermentability experiments were carried out of varying pH levels in synthetic media that includes acetic acid as the main inhibitors and hydrolysate supplemented with diverse nitrogen source. The results revealed that pH 7 exhibited the highest xylitol production, yielding 0.35 g/g. Furthermore, urea was found to be a highly promising and cost-effective substitute for yeast extract, as it yielded a comparable xylitol production of 0.31 g/g with marginal difference of only 0.01 g/g compared to yeast extract further highlights the viability of urea as the preferred option for reducing xylitol production cost. The absence of a significant difference between the synthetic media and hydrolysate, with only a marginal variance of 0.35 to 0.32 g/g, implies that acetic acid is indeed the primary constraint in xylitol production using PP hydrolysate. The study sheds light on PP biomass's potential for xylitol production, aligning economic benefits with environmental sustainability and waste management.

Matched MeSH terms: Xylitol*
Evaluation of in vitro corrosion behavior and biocompatibility of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron for bone scaffolds applications

Md Yusop AH, Wan Ali WFF, Jamaludin FH, Szali Januddi F, Sarian MN, Saad N, et al.

Biotechnol J, 2024 Mar;19(3):e2300464.
PMID: 38509814 DOI: 10.1002/biot.202300464

The present study evaluates the corrosion behavior of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron (PXDD140/HA-Fe) and its cell-material interaction aimed for temporary bone scaffold applications. The physicochemical analyses show that the addition of 20 wt.% HA into the PXDD polymers leads to a higher crystallinity and lower surface roughness. The corrosion assessments of the PXDD140/HA-Fe evaluated by electrochemical methods and surface chemistry analysis indicate that HA decelerates Fe corrosion due to a lower hydrolysis rate following lower PXDD content and being more crystalline. The cell viability and cell death mode evaluations of the PXDD140/HA-Fe exhibit favorable biocompatibility as compared to bare Fe and PXDD-Fe scaffolds owing to HA's bioactive properties. Thus, the PXDD140/HA-Fe scaffolds possess the potential to be used as a biodegradable bone implant.

Matched MeSH terms: Xylitol*
Development of a novel direct compressible co-processed excipient and its application for formulation of Mirtazapine orally disintegrating tablets

Loke YH, Chew YL, Janakiraman AK, Lee SK, Uddin ABMH, Goh CF, et al.

Drug Dev Ind Pharm, 2024 Jan;50(1):36-44.
PMID: 38149637 DOI: 10.1080/03639045.2023.2294095

INTRODUCTION: Orally disintegrating tablets (ODTs) are designed to dissolve in the oral cavity within 3 min, providing a convenient option for patients as they can be taken without water. Direct compression is the most common method used for ODTs formulations. However, the availability of single composite excipients with desirable characteristics such as good compressibility, fast disintegration, and a good mouthfeel suitable for direct compression is limited.
OBJECTIVE: This research was proposed to develop a co-processed excipient composed of xylitol, mannitol, and microcrystalline cellulose for the formulation of ODTs.
METHODS: A total of 11 formulations of co-processed excipients with different ratios of ingredients were prepared, which were then compressed into ODTs, and their characteristics were thoroughly examined. The primary focus was on evaluating the disintegration time and hardness of the tablets, as these factors are important in ensuring the ODTs meet the desired criteria. The model drug, Mirtazapine was then incorporated into the chosen optimized formulation.
RESULTS: The results showed that the formulation comprised of 10% xylitol, 10% mannitol and 80% microcrystalline cellulose demonstrated the fastest disintegration time (1.77 ± 0.119 min) and sufficient hardness (3.521 ± 0.143 kg) compared to the other formulations. Furthermore, the drug was uniformly distributed within the tablets and fully released within 15 min.
CONCLUSION: Therefore, the developed co-processed excipients show great potential in enhancing the functionalities of ODTs, offering a promising solution to improve the overall performance and usability of ODTs in various therapeutic applications.

Matched MeSH terms: Xylitol*
Fulltext Preparation of kenaf stem hemicellulosic hydrolysate and its fermentability in microbial production of xylitol by Escherichia coli BL21

Shah SSM, Luthfi AAI, Low KO, Harun S, Manaf SFA, Illias RM, et al.

Sci Rep, 2019 03 11;9(1):4080.
PMID: 30858467 DOI: 10.1038/s41598-019-40807-z

Kenaf (Hibiscus cannabinus L.), a potential fibre crop with a desirably high growth rate, could serve as a sustainable feedstock in the production of xylitol. In this work, the extraction of soluble products of kenaf through dilute nitric-acid hydrolysis was elucidated with respect to three parameters, namely temperature, residence time, and acid concentration. The study will assist in evaluating the performance in terms of xylose recovery. The result point out that the maximum xylose yield of 30.7 g per 100 g of dry kenaf was attained from 2% (v/v) HNO3 at 130 °C for 60 min. The detoxified hydrolysate was incorporated as the primary carbon source for subsequent fermentation by recombinant Escherichia coli and the performance of strain on five different semi-synthetic media on xylitol production were evaluated herein. Among these media, batch cultivation in a basal salt medium (BSM) afforded the highest xylitol yield of 0.35 g/g based on xylose consumption, which corresponded to 92.8% substrate utilization after 38 h. Subsequently, fermentation by E. coli in the xylose-based kenaf hydrolysate supplemented with BSM resulting in 6.8 g/L xylitol which corresponding to xylitol yield of 0.38 g/g. These findings suggested that the use of kenaf as the fermentation feedstock could be advantageous for the development of sustainable xylitol production.

Matched MeSH terms: Xylitol/biosynthesis; Xylitol/metabolism; Xylitol/chemistry
Immobilization of recombinant Escherichia coli on multi-walled carbon nanotubes for xylitol production

Abd Rahman NH, Md Jahim J, Abdul Munaim MS, A Rahman R, Fuzi SFZ, Md Illias R

Enzyme Microb Technol, 2020 Apr;135:109495.
PMID: 32146929 DOI: 10.1016/j.enzmictec.2019.109495

E. coli has been engineered to produce xylitol, but the production faces bottlenecks in terms of production yield and cell viability. In this study, recombinant E. coli (rE. coli) was immobilized on untreated and treated multiwalled carbon nanotubes (MWCNTs) for xylitol production. The immobilized rE. coli on untreated MWCNTs gave the highest xylitol production (5.47 g L-1) and a productivity of 0.22 g L-1 h-1. The doubling time for the immobilized cells increased up to 20.40 h and was higher than that of free cells (3.67 h). Cell lysis of the immobilized cells was reduced by up to 73 %, and plasmid stability improved by up to 17 % compared to those of free cells. Xylitol production using the optimum parameters (pH 7.4, 0.005 mM and 29 °C) achieved a xylitol production and productivity of 6.33 g L-1 and 0.26 g L-1 h-1, respectively. A seven-cycle repeated batch fermentation was carried out for up to 168 h, which showed maximum xylitol production of 7.36 g L-1 during the third cycle. Hence, this new adsorption immobilization system using MWCNTs is an alternative to improve the production of xylitol.

Matched MeSH terms: Xylitol/metabolism*
Fulltext Overliming effects on xylitol production from sago trunk hydrolysate

Mohamad, N.L., Mustapa Kamal, S.M., Abdullah, A.G.L.

Pertanika Journal of Science & Technology, 2011;19(2):415-422.
MyJurnal

Xylitol can be obtained from lignocellulosic materials containing xylose. However, the fraction of lignocellulose converted through dilute acid hydrolysis contains compounds that inhibit the fermenting micro-organisms. These inhibitors can be removed from the hydrolysate by detoxification method, prior to fermentation. This study describes effectiveness of overliming process to reduce the toxicity of hydrolysates generated from pre-treatment of sago trunk for xylitol production. The overliming pH 9 and 10 was studied and the results showed that pH 9 was showed 20% of sugar loss, which is low compared to pH 10. Candida tropicalis strain was used to evaluate the fermentability of overlimed sago trunk hydrolysate at pH 9 and non-overlimed hydrolysate medium. Meanwhile, Xylitol accumulation and productivity in the overlimed medium was found to be higher than the non-treated medium. The maximum production of xylitol was increased up to 74% and converted within 76 h. The results obtained improved the fermentation process when compared with the nontreated medium.

Matched MeSH terms: Xylitol
Effect of processing methods on xylitol-starch base co-processed adjuvant for orally disintegrating tablet application

Bin LK, Helaluddin ABM, Islam Sarker MZ, Mandal UK, Gaurav A

Pak J Pharm Sci, 2020 Mar;33(2):551-559.
PMID: 32276897

Orally disintegrating tablet (ODT) is a friendly dosage form that requires no access to water and serves as a solution to non-compliance. There are many co-processed adjuvants available in the market. However, there is no single product possesses all the ideal characteristics such as good compressibility, fast disintegration and good palatability for ODT application. The aim of this research was to produce a xylitol-starch base co-processed adjuvant which is suitable for ODT application. Two processing methods namely wet granulation and freeze drying were used to compare the characteristics of co-processed adjuvant comprising of xylitol, starch and crospovidone XL-10 mixed at various ratios. The co-processed excipients were compressed into ODT and physically characterized for powder flow, particle size, hardness, thickness, weight, friability, in-vitro disintegration time and in-situ disintegration time, lubricant sensitivity, dilution potential, Fourier transform infrared spectroscopy, scanning electronic microscopy and x-ray diffraction analysis. Formulation F6 was selected as the optimum formulation due to the fastest in-vitro (135.33±11.52 s) and in-situ disintegration time (88.67±13.56s) among all the formulations (p<0.05). Increase in starch component decreases disintegration time of ODT. The powder flow fell under the category of fair flow. Generally, it was observed that freeze drying method produced smaller particle size granules compared to wet granulation method. ODT produced from freeze drying method had shorter disintegration time compared to ODT from wet granulation batch. In conclusion, a novel co-processed excipient comprised of xylitol, starch and crospovidone XL-10, produced using freeze drying method with fast disintegration time, good compressibility and palatability was developed and characterized. The co-processed excipient is suitable for ODT application.

Matched MeSH terms: Xylitol/administration & dosage; Xylitol/chemical synthesis*
Fulltext A perspective bioproduction of xylitol by enzyme technology and future prospects

Rafiqul, I.S.M., Mimi Sakinah, A.M.

International Food Research Journal, 2012;19(2):405-408.
MyJurnal

Xylitol is a high value sugar alcohol with anticariogenic properties that is used as an ideal sweetener for diabetic patients. Industrially, xylitol is manufactured by catalytic reduction of pure xylose, which has
some disadvantages. The fermentation process has been studied as an alternative, but its viability is dependent on the optimization of several variables. This fermentation process on an industrial-scale is not feasible due to decreased productivity. Compared to the fermentation process, enzymatic method is expected to make a substantial increase in productivity. Enzymatic xylitol production from xylose exist in lignocellulosics is an attractive and promising alternative method to the chemical process. The enzymatic method might be able to overcome the disadvantages of the chemical process. This article reviews the literature on the processes for xylitol production and identifies further ways for improved xylitol production to compete with the current chemical process.

Matched MeSH terms: Xylitol
Ethanol production capability of Candida shehatae in mixed sugars and rice straw hydrolysate

Yuvadetkun P, Boonmee M

Sains Malaysiana, 2016;45:581-587.

Ethanol fermentations by Candida shehatae TISTR 5843 at low (20 g/L) and high (80 g/L) sugar concentrations with various glucose to xylose ratios were investigated. Glucose was a preferred substrate as it was consumed first at a faster consumption rate. The type of sugar and ratio between glucose and xylose did not have an effect on ethanol produced. The average ethanol concentrations were 7.99 g/L when using 20 g/L sugar and 27.82 g/L when using 80 g/L sugar. Small amounts of xylitol and glycerol as by-products were presented when using 20 g/L sugar. Xylitol appeared to be the main by-product at high xylose concentration with elevated concentrations as xylose is increased. When using rice straw hydrolysate containing 34.75 g/L glucose and 21.29 g/L xylose, 19.37 g/L ethanol was produced with the ethanol yield and ethanol productivity at 0.49 g/g and 0.20 g/L.h, respectively. However, xylose was not completely consumed after fermentation was complete.

Matched MeSH terms: Xylitol
Biochemical properties of xylose reductase prepared from adapted strain of Candida tropicalis

Rafiqul IS, Sakinah AM

Appl Biochem Biotechnol, 2015 Jan;175(1):387-99.
PMID: 25300602 DOI: 10.1007/s12010-014-1269-4

Xylose reductase (XR) is an intracellular enzyme, which catalyzes xylose to xylitol conversion in the microbes. It has potential biotechnological applications in the manufacture of various commercially important specialty bioproducts including xylitol. This study aimed to prepare XR from adapted strain of Candida tropicalis and to characterize it. The XR was isolated from adapted C. tropicalis, cultivated on Meranti wood sawdust hemicellulosic hydrolysate (MWSHH)-based medium, via ultrasonication, and was characterized based on enzyme activity, stability, and kinetic parameters. It was specific to NADPH with an activity of 11.16 U/mL. The enzyme was stable at pH 5-7 and temperature of 25-40 °C for 24 h and retained above 95 % of its original activity after 4 months of storage at -80 °C. The K m of XR for xylose and NADPH were 81.78 mM and 7.29 μM while the V max for them were 178.57 and 12.5 μM/min, respectively. The high V max and low K m values of XR for xylose reflect a highly productive reaction among XR and xylose. MWSHH can be a promising xylose source for XR preparation from yeast.

Matched MeSH terms: Xylitol/biosynthesis
Chemometric analysis of lipase-catalyzed synthesis of xylitol esters in a solvent-free system

Adnani A, Basri M, Chaibakhsh N, Ahangar HA, Salleh AB, Rahman RN, et al.

Carbohydr Res, 2011 Mar 1;346(4):472-9.
PMID: 21276966 DOI: 10.1016/j.carres.2010.12.023

Immobilized Candida antarctica lipase B-catalyzed esterification of xylitol and two fatty acids (capric and caproic acid) were studied in a solvent-free system. The Taguchi orthogonal array method based on three-level-four-variables with nine experiments was applied for the analysis and optimization of the reaction parameters including time, substrate molar ratio, amount of enzyme, and amount of molecular sieve. The obtained conversion was higher in the esterification of xylitol and capric acid with longer chain length. The optimum conditions derived via the Taguchi approach for the synthesis of xylitol caprate and xylitol caproate were reaction time, 29 and 18h; substrate molar ratio, 0.3 and 1.0; enzyme amount, 0.20 and 0.05g, and molecular sieve amount of 0.03g, respectively. The good correlation between the predicted conversions (74.18% and 61.23%) and the actual values (74.05% and 60.5%) shows that the model derived from the Taguchi orthogonal array can be used for optimization and better understanding of the effect of reaction parameters on the enzymatic synthesis of xylitol esters in a solvent-free system.

Matched MeSH terms: Xylitol/chemistry*
Fulltext Explorative Xylitol Detection from Lignocellulosic Biomass Fermentation of Coconut Husk Using HPLC C18 Column

Mariam-Aisha Fatima, Muhammad Fahmi Mehdin, Nurain Nasrudin, Neelam Shahab

Journal of Management & Science, 2018;16(2):29-38.
MyJurnal

Lignocellulosic biomass, found in wooden plant husks is a potent renewable material source which can be utilised to form various chemicals and biomaterials including polyols such as xylitol. Xylitol has been used commercially as an alternative to sucrose in many products as bulk sweetener in non-cariogenic confectionery as well as in diabetic diets and solutions for parenteral nutrition. Therefore, this study aims to optimise separation parameters of the Shimadzu high performance liquid chromatography (HPLC) (Model No: LC-20A) and quantify the potential of coconut husk as substrate for Candida albicans in producing xylitol using HPLC. Pretreatment to depolymerise components of biomass i.e. cellulose, hemicellulose and lignin were done using dilute acid hydrolysis method which yielded fermentable reducing sugars, xylose. Xylose is a monosaccharide with an aldehyde functional group, a reducing sugar which is then utilised and fermented by the yeast Candida albicans to form xylitol. In this study, the media used for fermenting pretreated coconut husk and Candida albicans is a synthetic defined (SD) minimal broth. Growth curves against concentration of reducing sugar were plotted to determine utilisation and production trends with specific mixes of carbon sources. The presence of reducing sugars were tested using 3,5-dinitrosalicylic acid (DNS) assay in pretreated coconut husk yielded 13.22 g/L. In order to analyse the product with HPLC, an existing protocol is modified for Hypersil GOLD™ C18 column with acetonitrile as the mobile phase. Results obtained from HPLC analyses using developed protocol suggested the formation of xylitol from the fermentation of pretreated husk by Candida albicans. These can be followed by purification of fermented media in obtaining a better separation of contaminating peaks.

Matched MeSH terms: Xylitol
Fulltext Caries preventive interventions in community-dwelling elders: a systematic review

Eleena Mohd Yusof, Mei, May Lei, Walls, Angus

Compendium of Oral Science, 2018;5(1):1-17.
MyJurnal

Objective: To conduct a systematic review of identifying the clinical efficacy of caries preventive interventions in community-dwelling elders. Background: As the human lifespan increases, the elders are known to retain their teeth for longer. Therefore, the need to uncover effective ways of preventing caries among this age group is relevant. Methods: A search was conducted using four databases: Cochrane, MEDLINE, EMBASE and Web of Science using the keywords (caries OR demineralization) AND prevention AND (adult OR aged). The titles and abstracts were initially screened for the use of caries prevention interventions. Studies were excluded based on the predetermined criteria. The full texts of the remaining studies were then evaluated. Results: Of 6952 articles identified from the search, fifty full texts were evaluated. Finally, ten studies were analyzed. One study found rinsing with 0.05% of NaF twice daily resulted in lower coronal caries increment. Another study reported the use of 1,100 ppm of NaF dentifrice twice daily showed lower percentage of coronal and root caries. A reduction of root caries was observed from using 5,000 ppm fluoridated toothpaste twice daily, annual professional 38% SDF solution application, six-monthly professional cleaning and APF gel application. The use of 0.12% CHX rinse and xylitol chewing gum did not show reduction of caries incidence. Conclusion: Toothbrushing with 5,000 ppm of NaF dentifrice, rinsing with 0.05% NaF, professional application of 38% SDF solution and APF gel may be effective at preventing caries among the elders.

Matched MeSH terms: Xylitol
Alternative sweeteners influence the biomass of oral biofilm

Abdul Razak F, Baharuddin BA, Akbar EFM, Norizan AH, Ibrahim NF, Musa MY

Arch Oral Biol, 2017 Aug;80:180-184.
PMID: 28448807 DOI: 10.1016/j.archoralbio.2017.04.014

OBJECTIVE: Compact-structured oral biofilm accumulates acids that upon prolonged exposure to tooth surface, causes demineralisation of enamel. This study aimed to assess the effect of alternative sweeteners Equal Stevia(®), Tropicana Slim(®), Pal Sweet(®) and xylitol on the matrix-forming activity of plaque biofilm at both the early and established stages of formation.
METHODS: Saliva-coated glass beads (sGB) were used as substratum for the adhesion of a mixed-bacterial suspension of Streptococcus mutans, Streptococcus sanguinis and Streptococcus mitis. Biofilms formed on sGB at 3h and 24h represented the early and established-plaque models. The biofilms were exposed to three doses of the sweeteners (10%), introduced at three intervals to simulate the exposure of dental plaque to sugar during three consecutive food intakes. The treated sGB were (i) examined under the SEM and (ii) collected for turbidity reading. The absorbance indicated the amount of plaque mass produced. Analysis was performed comparative to sucrose as control.
RESULTS: Higher rate of bacterial adherence was determined during the early compared to established phases of formation. Comparative to the sweeteners, sucrose showed a 40% increase in bacterial adherence and produced 70% more plaque-mass. Bacterial counts and SEM micrographs exhibited absence of matrix in all the sweetener-treated biofilms at the early phase of formation. At the established phase, presence of matrix was detected but at significantly lower degree compared to sucrose (p<0.05).
CONCLUSION: Alternatives sweeteners promoted the formation of oral biofilm with lighter mass and lower bacterial adherence. Hence, suggesting alternative sweeteners as potential antiplaque agents.

Matched MeSH terms: Xylitol
Biomimetic hydroxyapatite/poly xylitol sebacic adibate/vitamin K nanocomposite for enhancing bone regeneration

Dai Z, Dang M, Zhang W, Murugan S, Teh SW, Pan H

Artif Cells Nanomed Biotechnol, 2019 Dec;47(1):1898-1907.
PMID: 31066314 DOI: 10.1080/21691401.2019.1573183

Hydroxyapatite (HAP) is a significant bone mineral that establishes bone strength. HAP composites in combination with biodegradable and bioactive polymer poly xylitol sebacic adipate (PXSA) would result in a constant release at target sites. Numerous studies have shown that vitamin K (VK) might possess a vital function in bone metabolism. The purpose of the present study was to inspect the synthesized composite HAP/PXSA/VK in developing polymeric biomaterials composite for the application of bone tissue regeneration. FTIR, X-ray diffraction, SEM and TEM techniques were applied to characterize the prepared composites. The release of VK from the HAP/PXSA/VK composite was evidenced through UV-Vis spectroscopy. In vitro studies proved that the HAP/PXSA/VK composite is appropriate for mesenchymal stem cell culture. Compared to pure HAP prepared following the same method, HAP/PXSA/VK composite provided favourable microstructures and good biodegradation distinctiveness for the application of tissue engineering, as well as tissue in-growth characteristics and improved scaffold cell penetration. This work reveals that the HAP/PXSA/VK composites have the potential for applications in bone tissue engineering.

Matched MeSH terms: Xylitol
Development of biofilm-targeted antimicrobial wound dressing for the treatment of chronic wound infections

Ng SF, Leow HL

Drug Dev Ind Pharm, 2015;41(11):1902-9.
PMID: 25758412 DOI: 10.3109/03639045.2015.1019888

It has been established that microbial biofilms are largely responsible for the recalcitrance of many wound infections to conventional antibiotics. It was proposed that the efficacy of antibiotics could be optimized via the inhibition of bacterial biofilm growth in wounds. The combination of antibiofilm agent and antibiotics into a wound dressing may be a plausible strategy in wound infection management. Xylitol is an antibiofilm agent that has been shown to inhibit the biofilm formation. The purpose of this study was to develop an alginate film containing xylitol and gentamicin for the treatment of wound infection. Three films, i.e. blank alginate film (SA), alginate film with xylitol (F5) and alginate film with xylitol and gentamicin (AG), were prepared. The films were studied for their physical properties, swelling ratio, moisture absorption, moisture vapor transmission rate (MVTR), mechanical and rheology properties, drug content uniformity as well as in vitro drug release properties. Antimicrobial and antibiofilm in vitro studies on Staphylococcus aureus and Pseudomonas aeruginosa were also performed. The results showed that AG demonstrates superior mechanical properties, rheological properties and a higher MVTR compared with SA and F5. The drug flux of AG was higher than that of commercial gentamicin cream. Furthermore, antimicrobial studies showed that AG is effective against both S. aureus and P. aeruginosa, and the antibiofilm assays demonstrated that the combination was effective against biofilm bacteria. In summary, alginate films containing xylitol and gentamicin may potentially be used as new dressings for the treatment of wound infection.

Matched MeSH terms: Xylitol
Enzymatic Production of Bioxylitol from Sawdust Hydrolysate: Screening of Process Parameters

Rafiqul IS, Sakinah AM, Zularisam AW

Appl Biochem Biotechnol, 2015 Jun;176(4):1071-83.
PMID: 25904039 DOI: 10.1007/s12010-015-1630-2

Xylose-rich sawdust hydrolysate can be an economic substrate for the enzymatic production of xylitol, a specialty product. It is important to identify the process factors influencing xylitol production. This research aimed to screen the parameters significantly affecting bioxylitol synthesis from wood sawdust by xylose reductase (XR). Enzymatic bioxylitol production was conducted to estimate the effect of different variables reaction time (2-18 h), temperature (20-70 °C), pH (4.0-9.0), NADPH (1.17-5.32 g/L), and enzyme concentration (2-6 %) on the yield of xylitol. Fractional factorial design was followed to identify the key process factors. The screening design identified that time, temperature, and pH are the most significant factors influencing bioxylitol production among the variables with the values of 12 h, 35 °C, and 7.0, respectively. These conditions led to a xylitol yield of 71 % (w/w). This is the first report on the statistical screening of process variables influencing enzyme-based bioxylitol production from lignocellulosic biomass.

Matched MeSH terms: Xylitol/biosynthesis*

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