Xylose Research Articles

Toward the Rechargeable Aqueous Zinc Ion Batteries with Improved Overall Performance: Electrolyte with Surface Adsorptive Additive.

Aqueous zinc-ion batteries (AZIBs) with slightly acidic electrolytes process advantages such as high safety, competitive cost, and satisfactory electrochemical performance. However, the failure behaviors of both electrodes, regarding zinc dendrite growth, interfacial parasitic reactions, and the collapse of cathode materials hinder the practical application of ZIBs. To alleviate the issues of both anode and cathode at the same time, D-xylose (DX) is introduced to the electrolyte as a multifunctional additive. As a result, the side reaction of the anode is suppressed and the metallic deposition behavior is regulated due to the hydrogen bonding network reconstruction and preferential surface adsorption of DX; for the MnO2 cathode, the DX adsorption can help the interfacial charge transfer and increase the reactive sites. Benefiting from these merits, DX-optimized Zn//Zn battery displays reveal a prolonged lifespan of 6912h and an ultra-high cumulative capacity of 17.28Ahcm-2 at 5mAcm-2. With the function of water reactivity suppression, the Coulombic efficiency reaches 99.91% at 2mAcm-2; the Zn||MnO2 full batteries exhibit excellent cyclability over 2000 cycles at 5C with an increased capacity of 118.9mAhg-1, indicating the dual functions to both of the electrodes for AZIBs.

Stimbiotic supplementation and xylose-rich carbohydrates modulate broiler's capacity to ferment fibre.

Stimbiotics are a new category of feed additives that can increase fibre fermentability by stimulating fibre-degrading microbiota in the gut. The aim of this study was to test, ex vivo, if the microbiota of broilers fed a stimbiotic are better able to ferment different xylose-rich substrates in an ileal and a caecal environment. The ileal and caecal contents from broiler chickens fed a stimbiotic or from a control group were used as an inoculum in the ex vivo fermentation experiment. Different xylose-rich substrates including monomeric xylose (XYL), XOS with DP 2 to 6 (XOS), short DP XOS of 2 to 3 (sDP-XOS), long DP XOS of 4 to 6 (lDP-XOS) and de-starched wheat bran (WB), were added to each ileal and caecal inoculum in fermentation vessels. Total gas, short-chain fatty acids (SCFA) production, bacterial quantification, and carbohydrate utilisation were monitored for 9 h post-inoculation. No significant interactions were observed in any of the parameters measured in either the ileal or caecal contents (p > 0.05). Stimbiotic ileal inocula resulted in higher total gas (p < 0.001) and volatile fatty acid (VFA) (p < 0.001) production, increased numbers of Lactobacillus spp. (p < 0.001), and decreased numbers of Enterococcus spp. (p < 0.01) after 9 h regardless of the xylose-rich substrate added. Stimbiotic caecal inocula resulted in a higher ratio of VFA to branched-chain fatty acids (BCFAs) by up to +9% (p < 0.05). Ileal microbiota were found to preferentially metabolise WB, while caecal microbiota favoured XOS substrates, particularly lDP-XOS. These results indicate that stimbiotics can promote the abundance of lactic acid bacteria involved in the establishment of fibre-degrading bacteria and VFA content in the gut, which could have beneficial effects on broiler performance. Further, ileal and caecal microbiota differ in their utilisation of different substrates which may impact the effectiveness of different stimbiotic products.

P425 Approach to identify and isolate C. dubliniensis in laboratory and comparison of various methods for same

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMIntroduction: C. dubliniensis, a newly recognized fungal pathogen, is clinically significant as it develops a stable fluconazole-resistant phenotype on exposure to this antifungal in vitro. C. dubliniensis is overlooked and misidentified as it shares many phenotypic traits with C. albicans. Molecular methods developed to distinguish the two species are not readily applicable. So, an easy-to-perform and an accurate phenotypic test would be a valuable tool.Aim: This study first of its kind from Kashmir Valley (conducted in SKIMS-1200 bedded tertiary care hospital) evaluated seven phenotypic tests with PCR-RFLP as a gold standard. The best methodology for routine identification of this emerging pathogen was developed.Materials: A total of 206 Candida spp. were tested which included 186 in-house C. albicans strains and 20 C. dubliniensis strains. The in-house 186 C. albicans strains were isolated from cancer patients. A total of 500 patients with various malignancies were screened, patients on antifungal drugs and screened once were excluded. All strains were sensitive to both fluconazole and voriconazole. Among 22°C dubliniensis strains, 14 were provided by Dr. Ziauddin Khan (Professor and Chairman, Department of Microbiology, Kuwait University) and 6 by VPCI institute Delhi.Reference strains included in the study: C. albicans 90028; (National culture collection of pathogenic fungi (NCCPF), Department of Medical Microbiology PGIMER Chandigarh) C. dubliniensis (CD36) and (CBS 7987); provided by Dr. Ziauddin KhanMethodsPCR-RFLP using BlnI (AvrII) enzyme was done to confirm the identification of all isolates (Fig. 1). Seven phenotypic tests that were evaluated include Growth on hypertonic Sabouraud Dextrose Agar (SDA), Colony color on Crome Candida Differential Agar, Growth at 45°C, Assimilation of xylose (XYL), Colony color and Chlamydospore formation on Tobacco Agar, Germ tube formation at 39°C and Fluorescence on methyl blue SDA. The variety of tests applied makes our study one of the most detailed studies for the identification of C. dubliniensis till date.ResultsNo C. dubliniensis was found among the isolates recovered from cancer patients by PCR-RFLP.Phenotypic tests that showed the best results wereGrowth on Hypertonic SDAColony color on Crome Candida Differential AgarRelative growth at 45°C.Assimilation of xylose (XAM as well as DISCs)Germ tube formation at 39°C was most rapid. Phenotypic methods proved to be very cost-effective than PCR-RFLP. Based on our results of growth on Hypertonic SDA and XAM and also knowing the fact that 5% of C. dubliniensis assimilate xylose and give false results of xylose assimilation, we developed a novel medium ‘Hypertonic xylose agar medium’ (HXAM). HXAM proved to be 100% accurate, simple, easy to perform, and cost-effective.ConclusionFor routine identification of C. dubliniensis we recommend colony color on Crome Agar and growth on HXAM as they are simple, reliable, inexpensive, reproducible, and readily applicable methods. For retrospective evaluation of stored cultures, we recommend HXAM.Based on our observations, we propose a scheme for the identification of C. dubliniensis (Fig. 2).

Effects of ultrasound‐assisted enzymatic hydrolysis and monosaccharides on structural, antioxidant and flavour characteristics of Maillard reaction products from sweet potato protein hydrolysates

SummaryEffects of ultrasound (US)‐assisted enzymatic hydrolysis and different monosaccharides (arabinose; xylose, XY; galactose and glucose) on peptide structure, antioxidant activities and flavour characteristics of Maillard reaction products (MRP) from sweet potato protein hydrolysates were investigated. US markedly enhanced the MR progress, and USXY showed the lowest pH value of 5.04, the highest browning intensity and fluorescence intensity (P &lt; 0.05). FTIR results revealed significant peptide structure changes in USXY, USAR and USGA compared to other samples. USXY exhibited the highest Oxygen radical absorbance capacity (ORAC) value of 109.15 µg TE/mL, followed by USGA and USAR (94.07 and 93.41 µg TE/mL), respectively (P &lt; 0.05). USXY and USAR showed different aroma features as compared to other MRP (P &lt; 0.05). In addition, US enhanced umami, sweetness and sourness attributes and reduced bitterness of all MRP. USXY exhibited the highest umami intensity score (7.4), followed by USGA (7.3) and USAR (7.2), respectively. Partial least square regression analysis showed that the stronger umami taste was strongly correlated to aldehydes, thiophenes, MW 1000–3000 and 500–1000 Da peptides. Thus, US‐assisted enzymatic hydrolysis and MR with xylose (XY) could be a promising way to produce natural flavouring with improved antioxidant activity.

Determination of the Flavoring Components in Vitex doniana Fruit Following Hydrodistillation Extraction

In traditional medicine and aromatherapy, use of essential oils and their flavor compounds have been known for the management of various human diseases. The flavor structures of black plum (Vitex doniana) sweet fruit are unavailable though widely eaten by natives. Therefore, this research is aimed at using spectroscopic techniques to identify the chemical structure of the specific flavor in the syrup responsible for its unique aroma and taste. Hydrodistillation (HD) in a Clevenger-type apparatus and GC-MS (HD-GC-MS) were used to extract the essential oil and analyse the volatile compounds (VOCs) respectively from Vitex doniana sweet fruit. 24 different volatile compounds (VOCs) were identified and grouped into eight classes of organic compounds comprising of 6 terpenes, 5 carboxylic acids, 3 ethers, 2 alcohols, 2 ketones, 2 lactones, 2 aldehydes and 2 esters. It is noteworthy that GC-MS following hydrodistillation offers invaluable information about the aroma components of the fruit, because fingerprints of volatile compounds profiles using novel extraction methods are currently highly valued due to its importance to sensory properties of foodstuffs. Therefore, characterization of the aroma compounds as markers in putrefied and fresh fruits and their products are of great importance as a quality control parameter. The sugars were then identified using a combination of 1D 1H NMR and GC-MS. Characterization of the specific sugars in black plum fruit was done using GC-MS spectroscopic techniques via derivatization. This method converts the sugars in the sample to the respective trimethylsilyl-derivatives of the sugars, which are thermally stable, volatile and amenable for GC-MS analysis. The sugars identified are Alpha.-D-Glucopyranose, Glucopyranose, D-Glucose, d-(+)-Xylose, 2-Deoxy-pentose, Glucofuranoside, beta.-D-Galactopyranoside, D-Fructose, alpha.-DL-Arabinofuranoside, alpha.-DL-Lyxofuranoside, Ribitol, 2-Keto-d-gluconic acid, D-Xylofuranose and alpha.-D-Galactopyranose as obtained from their raw area percentage based on the total ion current. In conclusion, derivatization along with the coupling of GC with MS allows invaluable information about the composition and structure of sugars.

Evaluation of Steam Explosion Pretreatment and Enzymatic Hydrolysis Conditions for Agave Bagasse in Biomethane Production

The production of biofuels from lignocellulosic biomass includes a pretreatment step to alter the biomass structure and facilitate the enzymatic degradation of the polymers to obtain assimilable compounds. In this study, agave bagasse (AB) was used as a feedstock for obtaining methane, for which AB was pretreated with steam explosion and enzymatically hydrolyzed. The pretreatment conditions corresponded to severity factors (SFs) within a range from 1.65 to 2.89, while enzymatic hydrolysis was performed with enzyme loads of Cellic CTec2 within a range from 0.12 to 3.6 mgprotein g−1AB. The best global yields (including pretreatment and enzymatic hydrolysis) of total carbohydrates (TCs), glucose (GLU), xylose (XYL), and chemical oxygen demand (COD) were 0.7 g TC g−1AB, 0.12 g GLU g−1AB, 0.03 g XYL g−1AB, and 0.20 g O2 g−1AB obtained using 2.4 mgprotein g−1AB of Cellic CTec2 with agave bagasse pretreated with an SF of 2.41. The contribution of pretreatment to the global TC yield ranged from 13 to 34% for the different systems evaluated. The biochemical potential of methane (BMP) of hydrolysates (pretreatment at SF 2.41 and 2.4 mgprotein g−1AB of Cellic CTec2) was 0.284 ± 0.02 in NL CH4 g−1 COD with a COD removal of 78.4 ± 1.3. This BMP value was 40% higher than the BMP obtained in the system without enzymatic hydrolysis, indicating the impact of this step on conversion to biomethane. The results at the BMP level indicated the potential of this residue for biofuel production.

Boosting xylose consumption and Poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) production by recombinant Burkholderia sacchari

Boosting xylose consumption and Poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) production by recombinant Burkholderia sacchari

Fermentable sugars production from acid-catalysed steam exploded barley straw

Barley straw is being considered a potential lignocellulosic raw material for fuel-ethanol production. Ethanol production from lignocellulosic biomass consists in three main steps: pretreatment, enzymatic hydrolysis and fermentation. In order to improve the accessibility of the enzymes during enzymatic hydrolysis, a dilute phosphoric acid steam explosion pretreatment was applied. A three factor experimental design with temperature (160-200 oC), residence time (10 – 30 min) and phosphoric acid concentration (1 – 3 % w/v) as relevant factors was performed after a previous stage of overnight soaking. Once the pretreatment was done, both liquid and pretreated solids were separated by filtration and analysed. The pretreated solids were further subjected to enzymatic hydrolysis (S/L= 5 %, 50 oC, 150 rpm, 15 FPU / g substrate, pH = 4.8) and the released glucose was determined. Optimal pretreatment conditions were determined based on highest recovery of hemicellulosic sugars and minimum inhibitors in the liquid fraction, and highest concentration of glucose after enzymatic hydrolysis of the solid residue. The best operational conditions were found to be 160 oC pretreatment temperature, 30 min residence time and 2.88 % phosphoric acid concentration, which resulted in the recovery of 44.0 % of xylose in the liquid fraction together with 7.5 % of the initial glucose. The enzymatic hydrolysis of the pretreated solid in these conditions resulted in the release of 61.0 % of the glucose contained in the raw material.

Comparison of photodiode array, evaporative light scattering, and single-quadrupole mass spectrometric detection methods for the UPLC analysis of pyrolysis liquids

ABSTRACTIt is important to analyze pyrolysis liquids to evaluate the yield of valuable products as well as unfavorable by-products. This work focuses on choosing detectors for reversed-phase ultra high-performance liquid chromatography analysis of pyrolysis liquids. The linearity, sensitivity, precision, and recovery of photodiode array (PDA) detector, single-quadrupole mass spectrometer (MS), and evaporative light scattering (ELS) detector were compared for the quantitative determination of several typical compounds found in pyrolysis liquids. PDA and MS detectors were found to be suitable for the quantification of furans and phenol derivatives (furfural, vanillin, syringol), but sugars and their derivatives (glucose, xylose, levoglucosan) can be analyzed with MS or ELS detectors.

Synthesis of Nanofiltration Membrane Developed from Triethanolamine (TEOA) and Trimesoyl Chloride (TMC) for Separation of Xylose from Glucose

Synthesis of thin film composite (TFC) nanofilt ration (NF) membrane has experienced tremendous development since the concept of interfacial polymerisation (IP) was first introduced. One of its new application is on the separation of xylose from glucos e in biomass hydrolysate. In this present study, NF TFC membrane has been produced through interfacial poly merisation by manipulation the concentration of triethanolamine (TEOA) at 35 min reaction time with 0. 15 % w/v of trimesoyl chloride (TMC). The membrane was then characterised in term of their chemical and physical properties, and separation performance between xylose and glucose. The growth of thin layer f ilm depends on concentration of TEOA as the monomer and reaction time. As concentration of TEOA and re action time increased, the layer of the TFC becomes thicker thus decreases the permeability of the membrane. Contradicted to this study, the lowest and the highest permeability were recorded at 4 % w/v of TEOA and 8 % w/v of TEOA at reaction time of 35-min in TMC. The TFC membrane prepared with 4 % w/v TEOA has high in permeate flux, resultant in high xylose separation of 1.3. Low permeate flux but moderate xylose separation factor of 0.93 was obtained for the TFC membrane prepared with 8 % w/v TEOA.

Fabrication of Asymmetric Nanofiltration Flatsheet Membrane for the Separation of Acetic Acid from Xylose and Glucose

Malaysia palm oil based industries generate a huge amount of lignocellulose biomass wastes. These wastes can be utilized to produce chemicals and fuel. Lignocellulose biomass consists of hemicelluloses, cellulose and lignin. Cellulose and hemicelluloses portion need to be hydrolysed to release fermentable glucose and xylose for further processing. Biomass hydrolysis using acid is a simple method, but it also produces acetic acid inhibitor that can inhibit the microorganism during fermentation. In order to increase the yield of product as well as to elevate the rate of product, there is a need to remove this acetic acid inhibitor from the biomass hydrolysate. In the current study, asymmetric nanofiltration (NF) flat sheet membrane was fabricated for acetic acid removal. Five types of asymmetric NF membranes were produced with different formulation in term of polymeric material (polysulfone (PSf) and polyethersulfone (PES)), types of solvent (N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), ethanol, dimethylacetamide (DMAc)), and types of additive (polyvinylpyrrolidone (PVP), polyethylene glycol (PEG)]. The best separation factor of acetic acid over glucose (1.1607) and acetic acid over xylose (1.2985) were showed by the asymmetric membrane produced from 19.6 wt% PSf/ 74.8 % DMAc/ 5.6 % ethanol and 21% PSf/ 55.3 % NMP/ 23.7 % THF.

Effects of polyethersulfone membrane substrate on the separation performance of thin film composite membrane in biorefinery

This study was aimed to develop a customised thin film composite (TFC) membrane for the separation in biorefinery. After the biomass hydrolysis stage, sugars component (i.e. glucose and xylose) need further refinement to remove any inhibitor (i.e. acetic acid) that can decrease the yield of the product during the fermentation stage. Substrate layer properties and the condition of thin film formation during interfacial polymerisation (IP) influenced the performance of the TFC membrane. Not much attention is given on the effects of substrate membrane properties asmost support membranes were purchased commercially. Polyethersulfone (PES) membrane substrate was fabricated in the current study at different PES concentration range of 15 wt% to 23 wt%. IP was performed using the piperazine and trimesoyl chloride monomers. As the PES concentration in the membrane substrate increased, the pure water permeability (PWP) decreased. The PWP of the membrane substrate prepared from 15 % PES and 23 % PES were 231.67 ± 16.59 L/m2.h.bar and 24.49 ± 6.54 L/m2.h.bar. After the IP, the PWP decreased to the range of nanofiltration. The PWP value were 28.07 ± 5.42 L/m2.h.bar and 3.94 ± 1.21 L/m2.h.bar for the TFC membrane prepared using 15 % PES and 23 % PES membrane support. TFC membrane prepared using 23 % PES showed the rejection value 24.07 ± 5.96 % of xylose, 47.56 ± 1.99 % of glucose and 2.67 ± 1.05 % of acetic acid. This is corresponding to the ideal separation factor of 1.45 ± 0.06 for xylose/glucose, 1.86 ± 0.05 for acetic acid/glucose and 1.29 ± 0.09 for acetic acid/xylose.

Thin film composite hollow fiber membrane for separation in biorefinery

One of the newest applications of the membrane technology is for the separation of sugar component and inhibitor removal during biomass processing in biorefinery. Most of the membranes used in biorefinery were commercially purchased and not specifically customise for the biomass hydrolysate processing. In the current study, a series of thin film composite (TFC) hollow fiber membranes were fabricated to tailor the performance toward xylose/glucose refinement and acetic acid removal in biomass processing. Polysulfone (PSf) hollow fiber membrane support was prepared using 20 wt% PSf, 2 wt% polyvinylpyrrolidone K30 (PVP K30) and 78 wt% dimethylformamide (DMF) through dry/wet spinning process. Three types of aqueous monomers were studied in interfacial polymerisation process, which are piperazine (PIP), triethanolamine (TEOA) and polyethyleneimine (PEI). TFC hollow fiber membrane prepared using TEOA monomer showed the best performance for separation of biomass hydrolysate component. It exhibited rejection value 50.98 ± 4.11 % of xylose, 71.72 ± 3.92 % of glucose and 5.45 ± 1.93 % of acetic acid. This is corresponding to the ideal separation factor of 1.75 ± 0.10 for xylose/glucose, 3.42 ± 0.54 for acetic acid/glucose and 1.95 ± 0.20 for acetic acid/xylose.

Combination of Entrapment and Covalent Binding Techniques for Xylanase Immobilization on Alginate Beads: Screening Process Parameters

Xylanase are responsible enzyme for hydrolysis of xylan into many beneficial products such as xylose, xylitol and xylooligosaccharides. Due to industrial potential of xylanase, a large number of studies have become interested in their immobilisation to reduce the cost of enzyme. Immobilised enzymes are currently the object of interest due to its benefits over soluble or free enzyme applied in enzymatic hydrolysis. The aims of this study were to determine the suitable method for xylanase immobilisation and to identify the significant parameter which affecting the immobilisation yield by fractional factorial design (FFD). Immobilised xylanase was prepared using a single immobilisation techniques of entrapment and covalent binding and also a combination of entrapment and covalent binding techniques. The immobilisation conditions for xylanase which includes of sodium alginate concentration, calcium chloride concentration, agitation rate and enzyme loading were screened using FFD experimental design to determine the most significant parameters in affecting the efficiency of immobilised xylanase. The analysis of xylanase activity was determined using dinitrosalicyclic acid (DNS) method. The xylanase enzyme was successfully immobilised by entrapment in sodium alginate beads and covalent binding on the surface of beads by glutaraldehyde. The combination of entrapment and covalent binding showed the highest immobilisation yield of 65.81 % compared to a single technique which contributes only 31.99 % and 48.53 %. Glutaraldeyhde concentration showed the most significant parameters compared to the others parameter which gives about 69.01 % of contribution on the xylanase immobilisation yield. The study shows the efficiency of enzyme immobilisation could be improved by a combination of immobilisation techniques and determination of the most significant factors for xylanase immobilisation.

A Green Chemical Production: Obtaining Levulinic Acid from Pretreated Sugarcane Bagasse

The Bio Based Press wrote “The production of levulinic acid is gaining momentum”. Today, researches are focusing efforts to convert biomass on new chemicals platforms, including levulinic acid (LA), which has gained increased attention for being an attractive platform for products with high added value. LA can be obtained through the acid hydrolysis of some types of saccharides such as glucose and xylose, the constituent unit of cellulose and hemicelluloses. In this work, three substantial steps to convert biomass, in this case sugarcane bagasse, in LA were investigated. Sugarcane bagasse was pretreated with acid (121 °C, 1.0 % w/v H2SO4, and 80 min) and alkali delignificated (80 °C, 0.5 % w/v NaOH, and 90 min reaction time) both with 20 % w/v of solids loading. Experiments were carried in a discontinuous reactor at different variations of temperature (160, 170 and 180 °C), acid concentration (3, 7 and 5 % w/v H2SO4), hydrolysis reaction time (55, 75 and 95 min) and substrate loadings (6, 8 and 12 % w/v). This research has demonstrated that LA production at 170 °C, 5% w/v H2SO4, 75 min and 6 % w/v of solids loading conditions achieved a LA yield of 55.00 ± 0.36 % and selectivity about 45.65 ± 0.26 %.

Optimization of Acid Treatment of Cashew Peduncle for Ethanol and Xylitol Production

Due to the large amount of waste generated by industries and commitments for environment preservation, there has been a growing interest in the use of alternative energy sources for the production of bioproducts of added value such as ethanol and xylitol. In this context, cashew has been considered a promising alternative to meet the global demand in a more sustainable way. Thus, the aim of this study was to optimize the acid treatment of cashew peduncle for biotechnological production of ethanol and xylitol. Physicochemical analyseswere held for bagasse characterization, and sugars were assessed by HPLC (glucose, xylose and arabinose) and fermentation inhibitors (acetic acid, furfural and hydroxymethylfurfural) in the hydrolyzed liquor. The 23+3 factorial experimental design was applied with a total of 11 experiments to investigate the influence ofvariables temperature, bagasse/acid diluted and acid concentration to evaluate the release of pentoses (xylose and arabinose) and hexose (glucose) in the hydrolyzed liquor. The liquor from the acid treatment should operate under ratio conditions temperature at level +1 (160 °C), acid concentration and bagasse:diluted acid at level -1 (1% and 1:6), obtaining pentose yields (xylose and arabinose). It was observed that acid treatment liquor is very effective in providing high-susceptibility substrates for ethanol and xylitol production.

Preparation of Rice Husk Carbon-based Solid Acid Catalyst for the Dehydration of Xylose to Furfural†

Preparation of Rice Husk Carbon-based Solid Acid Catalyst for the Dehydration of Xylose to Furfural†

Xylobiose ameliorates hyperglycemia and dyslipidemia via regulating hepatic lipogenic genes in db/db mice

Diabetes mellitus (DM) is a metabolic disorder in glucose and fat metabolism and has become a major public concern in worldwide. Xylobiose consists of two molecules of xylose and is a major disaccharide in a well‐known sweetener, xylo‐oligosaccharide. Although it has been reported the hypoglycemic effect of xylo‐oligosaccharide, the physiological effect of xylobiose on blood glucose and lipogenesis has not been evaluated. The objective of study was to evaluate the hypoglycemic and hypolipogenic effect of xylobiose in db/db mice. Five‐ week old male C57BL/KsJ‐db/db mice were randomized into 3 groups as follows: (1) a control group of C57BL/6 mice that received AIN93G (Ctrl), (2) a diabetic control group of C57BL/KsJ‐db/db mice that received AIN93G (DB), and (3) a group that supplemented with 5% xylobiose as part of the total sucrose content of the diet (XB5). Mice were fed the experimental diets for 6 weeks. Supplementation of xylobiose reduced food and water intake and improved glucose tolerance by reducing the levels of oral glucose tolerance test area under the curve, fasting blood glucose, HbA1c, insulin, and HOMA‐IR. These results indicate xylobiose attenuates hyperglycemia by regulating insulin and blood glucose metabolism. In addition, xylobiose supplementation significantly decreased the levels of TG, total cholesterol, and LDL‐C. Histopathologically, fat accumulation in liver tissues was reduced in XB 5 group. Expressions of lipogenic genes, including, FAS, PPARγ, SREBP‐1C, SREBP‐2, ACC, and HMG‐CoA reductase in liver tissues were significantly down‐regulated by xylobiose supplementation. Furthermore, xylobiose supplementation suppressed the mRNA expressions of pro‐inflammatory cytokines, TNF‐α, IL‐1β, IL‐6, and MCP‐1 and phosphorylation of three MAPK, such as JNK/SAPK, p38, and ERK (1/2). Taken together, xylobiose exhibits considerable anti‐diabetic, hypolipogenic, and anti‐inflammatory alternation in db/db mice.Support or Funding InformationThis research was supported by High Value‐added Food Technology Development Program (Project number: 313024‐03‐2‐HD040), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea, and Brain Korea 21 Plus (Project No. 22A20130012143)

Xylose substrate as the only nutrient in the operation of microbial fuel cells

Microbial fuel cells are bioelectrochemical devices converting chemical energy of organic compounds (i.e. biomass) into electrical energy by catalytic reactions of microbes under anaerobic conditions. The operation of two-chamber microbial fuel cells by Shewanella putrefaciens and mesophilic anaerobic sludge was studied comparatively, using xylose and glucose as solo substrates during the experiments. It was found that higher electric power was generated by the multicultural system than by the monoculture.

A Kluyveromyces marxianus 2-deoxyglucose-resistant mutant with enhanced activity of xylose utilization.

Thermotolerant ethanologenic yeast Kluyveromyces marxianus is capable of fermenting various sugars including xylose but glucose represses to hamper the utilization of other sugars. To acquire glucose repression-defective strains, 33 isolates as 2-deoxyglucose (2-DOG)-resistant mutants were acquired from about 100 colonies grown on plates containing 2-DOG, which were derived from an efficient strain DMKU 3-1042. According to the characteristics of sugar consumption abilities and cell growth and ethanol accumulation along with cultivation time, they were classified into three groups. The first group (3 isolates) utilized glucose and xylose in similar patterns along with cultivation to those of the parental strain, presumably due to reduction of the uptake of 2-DOG or enhancement of its export. The second group (29 isolates) showed greatly delayed utilization of glucose, presumably by reduction of the uptake or initial catabolism of glucose. The last group, only one isolate, showed enhanced utilization ability of xylose in the presence of glucose. Further analysis revealed that the isolate had a single nucleotide mutation to cause amino acid substitution (G270S) in RAG5 encoding hexokinase and exhibited very low activity of the enzyme. The possible mechanism of defectiveness of glucose repression in the mutant is discussed in this paper. [Int Microbiol 18(4):235-244 (2015)].