Efficient xylose utilisation by microorganisms is of importance to the lignocellulose fermentation industry. The aim of this work was to develop constitutive catabolite repression mutants in a xylose-utilising recombinant Saccharomyces cerevisiae strain and evaluate the differences in xylose consumption under fermentation conditions. S. cerevisiae YUSM was constitutively catabolite repressed through specific disruptions within the MIG1 gene. The strains were grown aerobically in synthetic complete medium with xylose as the sole carbon source. Constitutive catabolite repressed strain YCR17 grew four-fold better on xylose in aerobic conditions than the control strain YUSM. Anaerobic batch fermentation in minimal medium with glucose-xylose mixtures and N-limited chemostats with varying sugar concentrations were performed. Sugar utilisation and metabolite production during fermentation were monitored. YCR17 exhibited a faster xylose consumption rate than YUSM under high glucose conditions in ...
The catabolism of glucose and xylose was studied in a wild type and creA deleted (carbon catabolite de-repressed) strain of Aspergillus nidulans. Both strains were cultivated in bioreactors with either glucose or xylose as the sole carbon source, or in the presence of both sugars. In the cultivations on single carbon sources, it was demonstrated that xylose acted as a carbon catabolite repressor (xylose cultivations), while the enzymes in the xylose utilisation pathway were also subject to repression in the presence of glucose (glucose cultivations). In the wild type strain growing on the sugar mixture, glucose repression of xylose utilisation was observed; with xylose utilisation occurring only after glucose was depleted. This phenomenon was not seen in the creA deleted strain, where glucose and xylose were catabolised simultaneously. Measurement of key metabolites and the activities of key enzymes in the xylose utilisation pathway revealed that xylose metabolism was occurring in the creA ...
article{0c9c6596-022a-424f-a1a1-682387e3dd78, abstract = {Disruption of the ZWF1 gene encoding glucose-6-phosphate dehydrogenase (G6PDH) has been shown to reduce the xylitol yield and the xylose consumption in the xylose-utilizing recombinant Saccharomyces cerevisiae strain TMB3255. In the present investigation we have studied the influence of different production levels of G6PDH on xylose fermentation. We used a synthetic promoter library and the copper-regulated CUP1 promoter to generate G6PDH-activities between 0% and 179% of the wild-type level. G6PDH-activities of 1% and 6% of the wild-type level resulted in 2.8- and 5.1-fold increase in specific xylose consumption, respectively, compared with the ZWF1-disrupted strain. Both strains exhibited decreased xylitol yields (0.13 and 0.19 g/g xylose) and enhanced ethanol yields (0.36 and 0.34 g/g xylose) compared with the control strain TMB3001 (0.29 g xylitol/g xylose, 0.31 g ethanol/g xylose). Cytoplasmic transhydrogenase (TH) from Azotobacter ...
Bioethanol production from lignocellulosic biomass, in particular xylose, is currently of great concern, given the abundance of this sugar in the world, because Saccharomyces cerevisiae, which is widely used for bioethanol production, is unable to naturally ferment xylose. The aim of this study was to obtain a novel yeast capable of stably producing ethanol from biomass containing xylose by protoplast fusion between S. cerevisiae and xylose-utilizing yeast. We describe a novel xylose-fermenting yeast strain, FSC1, developed for ethanol production by intergeneric hybridization between S. cerevisiae and Candida intermedia mutants by using a protoplast fusion technique. The characteristics of the FSC1 strain are reported with respect to xylose fermentation, morphology, gene, and protein expression. Mutation of the parental strains prior to protoplast fusion endowed the FSC1 strain with the ability to convert xylose to ethanol. Microscopic analysis confirmed that the parental and FSC1 strains produced
Saccharomyces cerevisiae ferments hexoses efficiently but is unable to ferment xylose. When the bacterial enzyme xylose isomerase (XI) from Thermus thermophilus was produced in S. cerevisiae, xylose utilization and ethanol formation were demonstrated. In addition, xylitol and acetate were formed. An unspecific aldose reductase (AR) capable of reducing xylose to xylitol has been identified inS. cerevisiae. The GRE3gene, encoding the AR enzyme, was deleted in S.cerevisiae CEN.PK2-1C, yielding YUSM1009a. XI fromT. thermophilus was produced, and endogenous xylulokinase from S.cerevisiae was overproduced in S.cerevisiae CEN.PK2-1C and YUSM1009a. In recombinant strains from which the GRE3 gene was deleted, xylitol formation decreased twofold. Deletion of the GRE3 gene combined with expression of the xylA gene fromT. thermophilus on a replicative plasmid generated recombinant xylose utilizing S.cerevisiae strain TMB3102, which produced ethanol from xylose with a yield of 0.28 mmol of C from ...
Biotechnology for Biofuels. RESEARCH Open Access. Systematic and evolutionary engineering of a xylose isomerase-based pathway in Saccharomyces cerevisiae for efficient conversion yields. Sun-Mi Lee1,2, Taylor Jellison1 and Hal S Alper1,3*. Abstract. Background: Efficient xylose fermentation by yeast would improve the economical and sustainable nature of biofuels production from lignocellulosic biomass. However, the efficiency of xylose fermentation by the yeast Saccharomyces cerevisiae is suboptimal, especially in conversion yield, despite decades of research. Here, we present an improved performance of S. cerevisiae in xylose fermentation through systematic and evolutionary engineering approaches. Results: The engineering of S. cerevisiae harboring xylose isomerase-based pathway significantly improved the xylose fermentation performance without the need for intensive downstream pathway engineering. This strain contained two integrated copies of a mutant xylose isomerase, gre3 and pho13 deletion ...
Xylose fermentation in yeast has been a target of research for years, yet not all the factors that may affect xylose fermentation perfomance of yeast strains are known. In this study, the mutant S. cerevisiae strain TMB 3400, which has good xylose fermentation properties, was compared with its parental strain to examine the factors behind the improved xylose utilization at protein level. The proteome of the parental and the mutant strains were characterized by difference in gel electrophoresis (DiGE) to quantitatively identify proteins that are expressed at altered levels in the mutant. The most significant changes detected by proteome analysis were the 6-10-fold increased levels of xylose reductase, xylitol dehydrogenase and transketolase (Tkl1) in the mutant, which is in accordance with previous knowledge about xylose metabolism in yeast. The level of acetaldehyde dehydrogenase (Ald6) was also significantly increased. In addition, several proteins homologous to proteins from yeast species ...
TY - JOUR. T1 - Stepwise metabolic adaption from pure metabolization to balanced anaerobic growth on xylose explored for recombinant Saccharomyces cerevisiae. AU - Klimacek, Mario. AU - Kirl, Elisabeth. AU - Krahulec, Stefan. AU - Longus, Karin. AU - Novy, Vera. AU - Nidetzky, Bernd. PY - 2014. Y1 - 2014. UR - http://www.microbialcellfactories.com/content/13/1/37/abstract. U2 - 10.1186/1475-2859-13-37. DO - 10.1186/1475-2859-13-37. M3 - Article. VL - 13. SP - 1. EP - 12. JO - Microbial cell factories JF - Microbial cell factories SN - 1475-2859. IS - 37. ER - ...
A substantial portion of placental function is committed to the regulation of nutrient transfer from the dam to the fetus, with glucose being the major substrate for conceptus metabolism. Due to its homomorphism with glucose, xylose can be used as tracer for the assessment of placental nutrient transfer capacity. This study was designed to evaluate transplacental permeability to xylose in bovine pregnancies on Days 90 and 180 of gestation. In Experiment 1, pregnant and nonpregnant females were infused into the jugular vein or into the allantoic sac with a 10% xylose solution to evaluate the maternal plasma xylose disappearance and the existence of feto-maternal xylose transfer, respectively. Glucose and xylose concentrations were determined in venous blood samples collected at 0, 15, 30, 60, 90, 120, 150, and 180 min. A materno-fetal but not a feto-maternal xylose transport was observed in both gestational periods. In Experiment 2, pregnant animals were slaughtered on Days 90 or 180 of ...
Industrial biotechnology aims to develop robust microbial cell factories, such as Saccharomyces cerevisiae, to produce an array of added value chemicals presently dominated by petrochemical processes. Xylose is the second most abundant monosaccharide after glucose and the most prevalent pentose sugar found in lignocelluloses. Significant research efforts have focused on the metabolic engineering of S similar to cerevisiae for fast and efficient xylose utilization. This study aims to metabolically engineer S similar to cerevisiae, such that it can consume xylose as the exclusive substrate while maximizing carbon flux to biomass production. Such a platform may then be enhanced with complementary metabolic engineering strategies that couple biomass production with high value-added chemical. Saccharomyces cerevisiae, expressing xylose reductase, xylitol dehydrogenase and xylulose kinase, from the native xylose-metabolizing yeast Pichia stipitis, was constructed, followed by a directed evolution strategy to
TY - JOUR. T1 - Production of biofuels and chemicals from xylose using native and engineered yeast strains. AU - Kwak, Suryang. AU - Jo, Jung Hyun. AU - Yun, Eun Ju. AU - Jin, Yong-Su. AU - Seo, Jin Ho. PY - 2019/3/1. Y1 - 2019/3/1. N2 - Numerous metabolic engineering strategies have allowed yeasts to efficiently assimilate xylose, the second most abundant sugar component of lignocellulosic biomass. During the investigation of xylose utilization by yeasts, a global rewiring of metabolic networks upon xylose cultivation has been captured, as opposed to a pattern of glucose repression. A clear understanding of the xylose-induced metabolic reprogramming in yeast would shed light on the optimization of yeast-based bioprocesses to produce biofuels and chemicals using xylose. In this review, we delved into the characteristics of yeast xylose metabolism, and potential benefits of using xylose as a carbon source to produce various biochemicals with examples. Transcriptomic and metabolomic patterns of ...
Recent advancements in omics measurement technologies have led to an ever-increasing amount of available experimental data that necessitate systems-oriented methodologies for efficient and systematic integration of data into consistent large-scale kinetic models. These models can help us to uncover new insights into cellular physiology and also to assist in the rational design of bioreactor or fermentation processes. Optimization and Risk Analysis of Complex Living Entities (ORACLE) framework for the construction of large-scale kinetic models can be used as guidance for formulating alternative metabolic engineering strategies. We used ORACLE in a metabolic engineering problem: improvement of the xylose uptake rate during mixed glucose-xylose consumption in a recombinant Saccharomyces cerevisiae strain. Using the data from bioreactor fermentations, we characterized network flux and concentration profiles representing possible physiological states of the analyzed strain. We then identified enzymes that
The development of inhibitor tolerant ethanologenic yeasts is one of the important challenges for a successful bioethanol production process from lignocellulose. Furthermore, an efficient microorganism for bioethanol production has to be able to ferment xylose together with glucose since xylose represents a large fraction in the lignocellulosic biomass. Weak acids and phenolic compounds are some of the prevalent inhibitors generated during pretreatment of lignocellulose and they will be present in the fermentation broth stressing the yeast affecting the fermentation performance. Although some studies on the effect of organic acids on fermenting microorganisms have been published, there is a lack of knowledge on the effect of phenolic compounds on yeast and more concretely about the effect on the xylose fermentation performance. In this study, the effect of acetic acid and vanillin on yeast growth on glucose and xylose will be elucidated using synthetic media mimicking lignocellulosic hydrolysates. It is
During cultivation on a mixture of xylose and glucose, Bacteroides xylanolyticus X5-1 showed neither diauxic growth nor a substrate preference. Xylose-limited continuous-culture cells were able to consume xylose and glucose both as single substrates and as mixed substrates without any lag phase. When glucose was the growth-limiting substrate, the microorganism was unable to consume xylose. However, in the presence of a small amount of glucose or pyruvate, xylose was utilized after a short lag phase. In glucose-limited cells, xylose isomerase was present at low activity but xylulose kinase activity could not be detected. On addition of a mixture of xylose and glucose, xylose isomerase was induced immediately and xylulose kinase was induced after about 30 min. The induction of the two enzymes was sensitive to chloramphenicol, showing de novo synthesis. Xylose uptake in glucose-grown cells was very low, but the uptake rate could be increased when incubated with a xylose-glucose mixture. The ...
Accepted name: D-xylose reductase. Reaction: xylitol + NAD(P)+ = D-xylose + NAD(P)H + H+ Other name(s): XylR; XyrA; msXR; dsXR; monospecific xylose reductase; dual specific xylose reductase; NAD(P)H-dependent xylose reductase; xylose reductase. Systematic name: xylitol:NAD(P)+ oxidoreductase. Comments: Xylose reductase catalyses the initial reaction in the xylose utilization pathway, the NAD(P)H dependent reduction of xylose to xylitol. Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: References:. 1. Neuhauser, W., Haltrich, D., Kulbe, K.D. and Nidetzky, B. NAD(P)H-dependent aldose reductase from the xylose-assimilating yeast Candida tenuis. Isolation, characterization and biochemical properties of the enzyme. Biochem. J. 326 (1997) 683-692. [PMID: 9307017]. 2. Nidetzky, B., Bruggler, K., Kratzer, R. and Mayr, P. Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity ...
Bioconversion of xylose-the second most abundant sugar in nature-into high-value fuels and chemicals by engineered Saccharomyces cerevisiae has been a long-term goal of the metabolic engineering community. Although most efforts have heavily focused on the production of ethanol by engineered S. cerevisiae, yields and productivities of ethanol produced from xylose have remained inferior as compared with ethanol produced from glucose. However, this entrenched focus on ethanol has concealed the fact that many aspects of xylose metabolism favor the production of nonethanol products. Through reduced overall metabolic flux, a more respiratory nature of consumption, and evading glucose signaling pathways, the bioconversion of xylose can be more amenable to redirecting flux away from ethanol towards the desired target product. In this report, we show that coupling xylose consumption via the oxidoreductive pathway with a mitochondrially-targeted isobutanol biosynthesis pathway leads to enhanced product ...
The permeability characteristics of D- and L-xylose and D- and L-arabinose have been compared in isolated intact rat diaphragm muscle preparations, in the absence and presence of exogenous insulin. In the absence of added insulin, these pentoses distribute in less than a third of the total cell water. In the presence of added insulin, intracellular distribution of all these pentoses is increased. L-Xylose and D-arabinose distribute in 50 per cent of the intracellular water, whereas D-xylose and L-arabinose distribute in 80 per cent of the cell water. A significant lag period was observed before the insulin effect upon the penetration of L-xylose and D-arabinose was evident whereas the effect upon D-xylose and L-arabinose was rapid. The lag period with L-xylose could be abolished by pretreating the tissues with insulin for 1 hour, but such pretreatment had little effect on D-xylose. These results indicate that insulin has a biphasic effect upon the monosaccharide exclusion system in diaphragm ...
article{3edb5e2c-caaf-4646-9ecb-432a6bbf667b, abstract = {ABSTRACT: BACKGROUND: Simultaneous saccharification and fermentation (SSF) is a promising process option for ethanol production from lignocellulosic materials. However, both the overall ethanol yield and the final ethanol concentration in the fermentation broth must be high. Hence, almost complete conversion of both hexoses and pentoses must be achieved in SSF at a high solid content. A principal difficulty is to obtain an efficient pentose uptake in the presence of high glucose and inhibitor concentrations. Initial glucose present in pretreated spruce decreases the xylose utilization by yeast, due to competitive inhibition of sugar transport. In the current work, prefermentation was studied as a possible means to overcome the problem of competitive inhibition. The free hexoses, initially present in the slurry, were in these experiments fermented before adding the enzymes, thereby lowering the glucose concentration. RESULTS: This work ...
D-Xylose is a five-carbon aldose (pentose, monosaccharide) that can be catabolized or metabolized into useful products by a variety of organisms. There are at least four different pathways for the catabolism of D-xylose: An oxido-reductase pathway is present in eukaryotic microorganisms. Prokaryotes typically use an isomerase pathway, and two oxidative pathways, called Weimberg and Dahms pathways respectively, are also present in prokaryotic microorganisms. This pathway is also called the "Xylose Reductase-Xylitol Dehydrogenase" or XR-XDH pathway. Xylose reductase (XR) and xylitol dehydrogenase (XDH) are the first two enzymes in this pathway. XR is reducing D-xylose to xylitol using NADH or NADPH. Xylitol is then oxidized to D-xylulose by XDH, using the cofactor NAD. In the last step D-xylulose is phosphorylated by an ATP utilising kinase, XK, to result in D-xylulose-5-phosphate which is an intermediate of the pentose phosphate pathway. Because of the varying cofactors needed in this pathway and ...
The anaerobic respiratory capabilities of the WT and the recombinant S. oneidensis were also determined under anaerobic conditions with xylose as the sole electron donor and fumarate as the electron acceptor. Similar to the aerobic conditions, the four genetically engineered strains grew faster than that of the WT strain. The recombinant strains XS and GS (harbouring the oxidoreductase pathway) consumed xylose at a rate of ~14.8, and ~17.2 μM/h, respectively, which had a faster xylose consumption rate than that of the strains XE and GE (harbouring the isomerase pathway, ~6.3 and ~9.7 μM/h, respectively) (Fig. 2c, d). Furthermore, the engineered strain GS could intake xylose faster than XS, which indicated that the glucose/xylose facilitator Gxf1 enabled a higher xylose transportation than that of the D-xylose-proton symporter XylT. It was revealed that sugar uptake via facilitated diffusion by Gxf1 required less energy (ATP) than proton symport XylT, and thus the facilitator protein would ...
Scheffersomyces stipitis ATCC ® 58785™ Designation: CBS 6054 [CCRC 21777, IFO 10063, NRRL Y-11545] Application: Bioethanol production
Scheffersomyces stipitis ATCC ® 58785D-2™ Designation: genomic DNA from CBS 6054 (ATCC 58785) Application: Bioethanol production
Background Many Firmicutes bacteria, including solvent-producing clostridia such as Clostridium acetobutylicum, are able to utilize xylose, an abundant carbon source in nature. Nevertheless, homology...
There is provided an engineered host cells comprising (a) one or more mutations in one or more endogenous genes encoding a protein associated with iron metabolism; and (b) at least one gene encoding a polypeptide having xylose isomerase activity, and methods of their use thereof.
Xylose or wood sugar is an aldopentose - a monosaccharide containing five carbon atoms and an aldehyde functional group. It has chemical formula C5H10O5 and is 40% as sweet as sucrose. Xylose is found in the embryos of most edible plants. The polysaccharide xylan, which is closely associated with cellulose, consists practically entirely of d-xylose. Corncobs, cottonseed hulls, pecan shells, and straw contain considerable amounts of this sugar. Xylose is also found in mucopolysaccharides of connective tissue and sometimes in the urine. Xylose is the first sugar added to serine or threonine residues during proteoglycan type O-glycosylation. Therefore xylose is involved in the biosythetic pathways of most anionic polysaccharides such as heparan sulphate and chondroitin sulphate. In medicine, xylose is used to test for malabsorption by administering a xylose solution to the patient after fasting. If xylose is detected in the blood and/or urine within the next few hours, it has been absorbed by the ...
The utilization of both C6 and C5 sugars is required for economical lignocellulosic bio-based processes. A co-culture system containing multiple strains of the same or different organisms holds promise for conversion of the sugar mixture available in different lignocellulosic feedstock into ethanol. Herein a co-culture kinetic model has been developed which can describe the co-cultivation of S. stipitis and S. cerevisiae for ethanol fermentation in mixed C6/C5 sugars. The predicted fermentation kinetics and ethanol production performance agreed well with experimental results, thus validating the model. The co-culture kinetic model has been implemented to design the optimal cell ratio for efficient conversion of rice straw or sugarcane bagasse feedstock into ethanol. The results reveal that the optimal co-culture system could enhance ethanol titer by up to 26 %, and ethanol productivity by up to 29 % compared to a single-strain culture. The maximum ethanol titer and productivity reached by the optimized
Carbohydrates: me, Carbon-Dioxide: bi, Carbon-Isotopes, Cell-Membrane: me, Culture-Media, Enzyme-Repression, Escherichia-Coli: en, gd, me, Galactose, Glucose: me, Glycosides: me, Lactose: me, Mannose: me, Xylose: me. ...
Intracellular proteome of A. niger grown on xylose or maltose. Comparative analysis of the intracellular proteome of A. niger AB1.13 grown to late exponential/e
In an application of the presented high-density microarray, we identify a carbon source-based response conserved in three aspergilli. The design of the study involving three different species, grown on three different defined minimal media, at three different values of pH, increases the likelihood of the found genes to be the true conserved "core" response to growth on xylose and not responses relying on an extra factor in addition to xylose (with the possible exception of abundant oxygen). We also believe this approach validates our argument that the xylanolytic transcriptional activator XlnR is a conserved system, even though it has not previously been studied in A. nidulans. Backed by the finding that the 5′-GGNTAAA-3′ motif is present and in some cases conserved as syntenic regions in all three species, we propose that the motif is indeed a XlnR motif and conserved in A. nidulans, A. niger, and A. oryzae. As a point of interest, a study of the homologous genes and their promoter regions ...
A 33-year-old white homosexual man with AIDS and Kaposi sarcoma was seen because of diarrhea of 3 months duration and 11 kg weight loss. He claimed 10 to 40 bowel movements per day, which were often malodorous, awakened him from sleep, and were associated with cramping but not tenesmus. The volume, consistency, and frequency varied. Diarrheal volume roughly correlated with the volume of food consumed and was worsened by fatty foods and dairy products. Nonspecific antidiarrheal medications brought partial relief of symptoms. He had no fever, and a physical examination was unremarkable. Stool examinations for enteric bacteria and parasites were negative on three occasions. The patient was severely immunosuppressed, with a CD4 lymphocyte count of 5/mm3 (normal range, 532 to 1571 mm3). D-Xylose absorption was subnormal, with serum concentrations of 0.84 and 0.62 mmol/L 1 and 2 hours after the test dose (normal range, 1.3 to 3.3 mmol/L), and urinary xylose excretion of 0.056 (normal, ,0.20). Upper ...
ID PISTI1_1_PE967 STANDARD; PRT; 362 AA. AC PISTI1_1_PE967; A3GHJ2; DT 00-JAN-0000 (Rel. 1, Created) DT 00-JAN-0000 (Rel. 2, Last sequence update) DT 00-JAN-0000 (Rel. 3, Last annotation update) DE Flags: Fragments; DE SubName: Full=Predicted protein;Flags: Fragment; (PISTI1_1.PE967). GN ORFNames=PICST_53517; OS SCHEFFERSOMYCES STIPITIS CBS 6054. OC Eukaryota; Fungi; Dikarya; Ascomycota; Saccharomycotina; Saccharomycetes; OC Saccharomycetales; Debaryomycetaceae; Scheffersomyces. OX NCBI_TaxID=322104; RN [0] RP -.; RG -.; RL -.; CC -!- SEQ. DATA ORIGIN: Translated from the HOGENOM CDS PISTI1_1.PE967. CC Pichia stipitis (strain CBS 6054 / NRRL Y-11545 / IFO 10063 / ATCC 5878 CC chromosome 1, complete sequence. CC -!- ANNOTATIONS ORIGIN:A3GHJ2_PICST CC -!- SIMILARITY: Contains 1 protein kinase domain. CC -!- GENE_FAMILY: HOG000233016 [ FAMILY / ALN / TREE ] DR UniProtKB/Swiss-Prot; A3GHJ2; -. DR EMBL; AAVQ01000002; EAZ63064.2; -; Genomic_DNA. DR RefSeq; XP_001387087.2; XM_001387050.1. DR ...
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Ha S.J., Galazka J.M., Rin Kim S., Choi J.H., Yang X., Seo J.H., Louise Glass N., Cate J.H., & Jin Y.S.Engineered Saccharomyces cerevisiae capable of simultaneous cellobiose and xylose fermentation. Proc Natl Acad Sci U S A. 108, 504-509 (2011) [http://www.pnas.org/content/108/2/504.abstract Link], [http://openwetware.org/images/8/80/Ha_PNAS.pdf PDF], [http://openwetware.org/images/d/d3/Ha_PNAS_SI.pdf Supporting Information], [http://www.pnas.org/content/108/2/435.full In This Issue-PNAS], [http://www.physorg.com/news/2010-12-scientists-major-obstacles-cellulosic-biofuel.html Related News ...
Kim, S.R., Skerker, J.M., Kang, W., Lesmana, A., Wei, N., Arkin, A.P. & Jin, Y.S. Rational and evolutionary engineering approaches uncover a small set of genetic changes efficient for rapid xylose fermentation in Saccharomyces cerevisiae. PLOS One [http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0057048?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+plosone%2FPLoSONE+(PLoS+ONE+Alerts%3A+New+Articles) Link ...
It can be ensured by inoculating culture on xylose lysine deoxycholate (XLD) agar plate. As it is selective agar for salmonella. They can ferment the sugar xylose and produce acid. They appear in yellow color on XLD plate.. ...
Industrial forensics and failure analysis expertise covering metallurgical, electronic device, concrete, and specialty chemicals/coatings.
ID G3ASN4_SPAPN Unreviewed; 199 AA. AC G3ASN4; DT 16-NOV-2011, integrated into UniProtKB/TrEMBL. DT 16-NOV-2011, sequence version 1. DT 25-OCT-2017, entry version 23. DE RecName: Full=Translation machinery-associated protein 22 {ECO:0000256,RuleBase:RU361273}; GN ORFNames=SPAPADRAFT_142498 {ECO:0000313,EMBL:EGW30720.1}; OS Spathaspora passalidarum (strain NRRL Y-27907 / 11-Y1). OC Eukaryota; Fungi; Dikarya; Ascomycota; Saccharomycotina; OC Saccharomycetes; Saccharomycetales; Debaryomycetaceae; Spathaspora. OX NCBI_TaxID=619300 {ECO:0000313,Proteomes:UP000000709}; RN [1] {ECO:0000313,EMBL:EGW30720.1, ECO:0000313,Proteomes:UP000000709} RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=NRRL Y-27907 / 11-Y1 {ECO:0000313,Proteomes:UP000000709}; RX PubMed=21788494; DOI=10.1073/pnas.1103039108; RA Wohlbach D.J., Kuo A., Sato T.K., Potts K.M., Salamov A.A., RA LaButti K.M., Sun H., Clum A., Pangilinan J.L., Lindquist E.A., RA Lucas S., Lapidus A., Jin M., Gunawan C., Balan V., Dale B.E., RA ...
Size-resolved aerosol samples for subsequent quantitative determination of polymer sugars (polysaccharides) after hydrolysis to their subunit monomers (monosaccharides) were collected in surface air over the central Arctic Ocean during the biologically most active summer period. The analysis was carried out by novel use of liquid chromatography coupled with highly selective and sensitive tandem mass spectrometry. Polysaccharides were detected in particle sizes ranging from 0.035 to 10 mu m in diameter with distinct features of heteropolysaccharides, enriched in xylose, glucose + mannose as well as a substantial fraction of deoxysugars. Polysaccharides, containing deoxysugar monomers, showed a bimodal size structure with about 70% of their mass found in the Aitken mode over the pack ice area. Pentose (xylose) and hexose (glucose + mannose) had a weaker bimodal character and were largely found with super-micrometer sizes and in addition with a minor sub-micrometer fraction. The concentration of ...
chitosanase (EC 3.2.1.132); cellulase (EC 3.2.1.4); licheninase (EC 3.2.1.73); endo-1,4-β-xylanase (EC 3.2.1.8); reducing-end-xylose releasing exo-oligoxylanase (EC 3.2.1.156 ...
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Background: Phenotypes exhibited by microorganisms can be useful for several purposes, e. g., ethanol as an alternate fuel. Sometimes, the target phenotype maybe required in combination with other phenotypes, in order to be useful, for e. g., an industrial process may require that the organism survive in an anaerobic, alcohol rich environment and be able to feed on both hexose and pentose sugars to produce ethanol.
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In this work, we rewired the xylose isomerase assimilation and mitochondrial isobutanol production pathways in the budding yeast Saccharomyces cerevisiae. We then increased the flux through these pathways by making gene deletions of BAT1, ALD6, and PHO13, to develop a strain (YZy197) that produces as much as 4 g/L of BCHAs (3.10 ± 0.18 g isobutanol/L and 0.91 ± 0.02 g 2-methyl-1-butanol/L) from xylose. This represents approximately a 28-fold improvement on the highest isobutanol titers obtained from xylose previously reported in yeast and the first report of 2-methyl-1-butanol produced from xylose. The yield of total BCHAs is 57.2 ± 5.2 mg/g xylose, corresponding to ~ 14% of the maximum theoretical yield. Respirometry experiments show that xylose increases mitochondrial activity by as much as 7.3-fold compared to glucose. ...
Exogenous anthrahydroquinone-2,6-disulfonate specifically increases xylose utilization during mixed sugar fermentation by Clostridium beijerinckii NCIMB ...
The xylose cluster of Lactobacillus pentosus consists of five genes, two of which, xylAB, form an operon and code for the enzymes involved in the catabolism of xylose, while a third encodes a regulatory protein, XylR. By introduction of a multicopy plasmid carrying the xyl operator and by disruption of the chromosomal xylR gene, it was shown that L. pentosus xylR encodes a repressor. Constitutive expression of xylAB in the xylR mutant is repressed by glucose, indicating that glucose repression does not require XylR. The xylR mutant displayed a prolonged lag phase compared to wild-type bacteria when bacteria were shifted from glucose to xylose medium. Differences in the growth rate in xylose medium at different stages of growth are not correlated with differences in levels of xylAB transcription in L. pentosus wild-type or xylR mutant bacteria but are positively correlated in Lactobacillus casei with a plasmid containing xylAB. Glucose repression was further investigated with a ccpA mutant. An ...
Production of D-xylonate by the yeast S. cerevisiae provides an example of bioprocess development for sustainable production of value-added chemicals from cheap raw materials or side streams. Production of D-xylonate may lead to considerable intracellular accumulation of D-xylonate and to loss of viability during the production process. In order to understand the physiological responses associated with D-xylonate production, we performed transcriptome analyses during D-xylonate production by a robust recombinant strain of S. cerevisiae which produces up to 50 g/L D-xylonate. Comparison of the transcriptomes of the D-xylonate producing and the control strain showed considerably higher expression of the genes controlled by the cell wall integrity (CWI) pathway and of some genes previously identified as up-regulated in response to other organic acids in the D-xylonate producing strain. Increased phosphorylation of Slt2 kinase in the D-xylonate producing strain also indicated that D-xylonate production
Catalyzes the initial reaction in the xylose utilization pathway by reducing D-xylose into xylitol. Xylose is a major component of hemicelluloses such as xylan. Most fungi utilize D-xylose via three enzymatic reactions, xylose reductase (XR), xylitol dehydrogenase (XDH), and xylulokinase, to form xylulose 5-phosphate, which enters pentose phosphate pathway (By similarity).
In enzymology, a xylose isomerase (EC 5.3.1.5) is an enzyme that catalyzes the interconversion of D-xylose and D-xylulose. This enzyme belongs to the family of isomerases, specifically those intramolecular oxidoreductases interconverting aldoses and ketoses. The isomerase has now been observed in nearly a hundred species of bacteria. Xylose-isomerases are also commonly called fructose-isomerases due to their ability to interconvert glucose and fructose. The systematic name of this enzyme class is D-xylose aldose-ketose-isomerase. Other names in common use include D-xylose isomerase, D-xylose ketoisomerase, and D-xylose ketol-isomerase. The activity of D-xylose isomerase was first observed by Mitsuhashi and Lampen in 1953 in the bacterium Lactobacillus pentosus. Artificial production through transformed E.coli have also been successful. In 1957, the D-xylose isomerase activity on D-glucose conversion to D-fructose was noted by Kooi and Marshall. It is now known that isomerases have broad ...
Bioprospecting is an effective way to find novel enzymes from strains with desirable phenotypes. Such bioprospecting has enabled organisms such as Saccharomyces cerevisiae to utilize nonnative pentose sugars. Yet, the efficiency of this pentose catabolism (especially for the case of arabinose) remains suboptimal. Thus, further pathway optimization or identification of novel, optimal pathways is needed. Previously, we identified a novel set of xylan catabolic pathway enzymes from a superior pentose-utilizing strain of Ustilago bevomyces. These enzymes were used to successfully engineer a xylan-utilizing S. cerevisiae through a blended approach of bioprospecting and evolutionary engineering. Here, we expanded this approach to xylose and arabinose catabolic pathway engineering and demonstrated that bioprospected xylose and arabinose catabolic pathways from U. bevomyces offer alternative choices for enabling efficient pentose catabolism in S. cerevisiae. By introducing a novel set of xylose ...
D-Xylose or L-arabinose-consuming S. cerevisiae strains have previously been independently developed by introduction of heterologous enzymes necessary for the assimilation of either of the sugars [6, 7, 10-12]. However, co-fermentation of the two pentose sugars by S. cerevisiae has not, to the best of our knowledge, previously been reported. We have introduced both the arabinose and the xylose pathways in S. cerevisiae strains to investigate the effects and possible limitations of the combined metabolism of the two pentoses. Xylose utilization was enabled by overexpression of the P. stipitis genes coding for XR and XDH as well as the endogenous XK through chromosomal integration. Arabinose assimilation was enabled through heterologous expression of the bacterial arabinose pathway consisting of L-arabinose isomerase (AraA), L-ribulokinase (AraB) and L-ribulose-5-P-4-epimerase (AraD) genes.. The combination of xylose and arabinose pathways was first tested in a laboratory strain. However, ...