Although Klason is generally credited as being the first to use sulfuric acid for lignin analysis, Sherrard and Harris (11 ) credit the use of sulfuric acid to Fleschsig in 1883, Ost and Wilkening in 1912, and König and Rump in 1913. According to Harris (12 ), Fleschsig, in 1883, dissolved cotton cellulose and converted it nearly quantitatively into sugars using strong sulfuric acid followed by dilution and heating. According to Browning (13 ), Ost and Wilkening introduced the use of 72 wt % sulfuric acid for lignin determinations in 1910. A translated paper by Heuser (14 ) credited König and Ost and Wilkening for the sulfuric acid lignin method. Dore (15 ) described several improved analytical methods (cellulose, lignin, soluble pentosans, mannan, and galactan) for the summative analysis of coniferous woods. The discrepancies in attribution may be due to differing definitions for the method cited (e.g., first to use acid to determine lignin, first to use sulfuric acid, first to use 72 wt % sulfuric acid, etc.) and to missed citations across continental distances in the early 20th century.
Xylose
It is an important precursor for the production of biofuels and biochemicals.
Xylose can be obtained from agricultural residues and lignocellulosic biomass through various pretreatment and hydrolysis processes.
Optimizing xylose research and production is crucial for advancing sustainable bioeconomy.
PubCompare.ai, an AI-driven platform, can help researchers locate, compare, and identify the best protocols and products for their xylose studies, enhancing reproducibility and accuracy.
This innovative tool empowers scientists to experience the future of scientific research and accelerate progress in xylose utilization.
Most cited protocols related to «Xylose»
Although Klason is generally credited as being the first to use sulfuric acid for lignin analysis, Sherrard and Harris (11 ) credit the use of sulfuric acid to Fleschsig in 1883, Ost and Wilkening in 1912, and König and Rump in 1913. According to Harris (12 ), Fleschsig, in 1883, dissolved cotton cellulose and converted it nearly quantitatively into sugars using strong sulfuric acid followed by dilution and heating. According to Browning (13 ), Ost and Wilkening introduced the use of 72 wt % sulfuric acid for lignin determinations in 1910. A translated paper by Heuser (14 ) credited König and Ost and Wilkening for the sulfuric acid lignin method. Dore (15 ) described several improved analytical methods (cellulose, lignin, soluble pentosans, mannan, and galactan) for the summative analysis of coniferous woods. The discrepancies in attribution may be due to differing definitions for the method cited (e.g., first to use acid to determine lignin, first to use sulfuric acid, first to use 72 wt % sulfuric acid, etc.) and to missed citations across continental distances in the early 20th century.
The concentration of xylose and XA were detected by high-performance anion-exchange chromatography (HPAEC) coupled with pulsed amperometric detector (Thermo ICS-5000). NaOH (100 mM) was used as mobile phase at flow rate of 0.3 mL/min. The separation column used was CarboPac™ PA200. The titer of erythritol, erythrulose, 1,3-PG and 3-HPA were measured by high-performance liquid chromatography (HPLC) (Agilent 1100 series) equipped with Carbohydrate Ca++ 8um HyperRez XP Column and deionized water, after ultrasound, was used as mobile phase at 0.6 mL/min.
Five parallel assays were performed for each experiment.
Trichoderma reesei (H. jecorina) QM6a wild‐type strain (ATCC 13631) was used as the parental strain to construct deletions of Δvel1. CBS999.97 MAT1‐1 and MAT1‐2 strains and several other wild‐type and mutant strains from different sources were included in this study to set up informative crosses (Table
Propagation of strains was performed on 3% (w/v) malt extract agar (Merck, Darmstadt, Germany). Crossing experiments were made on 2% (w/v) malt extract agar at 22°C in daylight (cycles of 12 h light–12 h dark) or constant darkness. Therefore, strains were grown on opposite sides of petri dishes and were evaluated for fruiting body formation and ascospore discharge 7 and 20 days after inoculation respectively. For evaluation of conidiation in QM6a Δvel1, Mandels–Andreotti (MA) medium (Mandels and Andreotti,
For transcriptional analysis, the strains were pre‐cultured on 3% (w/v) malt extract agar in constant darkness for at least 3 days. Inoculation of strains was performed on 2% (w/v) malt extract agar plates covered with cellophane to facilitate harvesting. To study gene expression in the course of sexual development, the strains were inoculated on both sides of the petri dishes and the mycelia of the partner strains were harvested at the stage of contact (3 days after inoculation). As the mutant strains have growth defects compared with wild‐type strains, they were inoculated in different distances from the opposite mating strain on petri dishes in order to obtain the contact stage of mycelia for the mutant strains at consistent times. Five plates at the stage of contact were pooled and at least two biological replicates were used for quantitative reverse transcription polymerase chain reaction (qRT‐PCR) analysis. In order to compare the obtained data with asexual growth, strains were grown alone on plates and the mycelia were harvested at the time points corresponding to the contact of strains in sexual development. The strains were grown under cycles of 12 h light–12 h darkness at 22°C (1800 lux).
For cellulase screening, strains were grown on plates with MA medium containing 1% (w/v) carboxymethylcellulose (CMC) (Sigma Aldrich) and after 2 days were stained with Congo red (0.1% w/v solution in water) (Roth, Karlsruhe, Germany), which stains cellulose (Carder,
One microlitre of the PCR product containing plasmid multimers was mixed with 100 µl of the supercompetent cells in a plastic test tube and cultivated at 37°C with shaking at 200 r.p.m. for 90 min. An aliquot of the transformed cells was diluted by 103‐ to 104‐fold for estimating the transformation efficiency. To facilitate the further segregation of different clones in the same cell (Shafikhani et al., 1997 (link)), the rest of the transformed cells were diluted into 10 ml of M9 minimal medium containing 5 µg ml−1 chloramphenicol and grown at 37°C for 14 h. The cell cultures were then diluted by 20‐fold with the same medium and grown for an additional 8 h. The serial diluted transformants were spread on LBR plates containing 5 µg ml−1 chloramphenicol and incubated at 37°C for 20 h. Positive colonies that were surrounded with big and clear halo zones were selected for further characterization and DNA sequencing using the primer pair P9/P10.
Most recents protocols related to «Xylose»
Example 1
This example describes the generation of a marker-free B. subtilis strain expressing allulose epimerase. Briefly, in a first step, a B. subtilis strain was transformed with a cassette encoding the BMCGD1 epimerase and including an antibiotic resistance marker. This cassette recombined into the Bacillus chromosome and knocked out 8 kb of DNA, including a large sporulation gene cluster and the lysine biosynthesis gene lysA. In a second step, a second cassette was recombined into the B. subtilis chromosome, restoring the lysA gene and removing DNA encoding the antibiotic resistance. E. coli strain 39 A10 from the Keio collection was used to passage plasmid DNA prior to transformation of B. subtilis. The relevant phenotype is a deficiency in the DNA methylase HsdM in an otherwise wild-type K-12 strain of E. coli.
In detail, a cassette of 5120 bp (SEQ ID NO:1; synthetic DNA from IDT, Coralville, Iowa) was synthesized and cloned into a standard ampicillin resistant pIDT vector. The synthetic piece encoded 700 bp upstream of lysA on the B. subtilis chromosome, the antibiotic marker cat (651 bp), the DNA-binding protein lad (1083 bp), and the allulose epimerase (894 bp), and included 700 bp of homology in dacF. This vector was transformed into E. coli strain 39 A10 (Baba et al., 2006), and plasmid DNA was prepared and transformed into B. subtilis strains 1A751 and 1A976.
Transformants were selected on LB supplemented with chloramphenicol. The replicon for pIDT is functional in E. coli but does not work in Gram positive bacteria such as B. subtilis. The colonies that arose therefore represented an integration event into the chromosome. In strain 1A751, the colony morphology on the plates was used to distinguish between single and double recombination events. The double recombination event would knock out genes required for sporulation, whereas the single recombination would not. After three days on LB plates, colonies capable of sporulation were brown and opaque; sporulation-deficient colonies were more translucent.
B. subtilis strain 1A976 with the allulose epimerase cassette is auxotrophic for histidine and lysine and can achieve very high transformation efficiency upon xylose induction. A 1925 bp synthetic DNA (SEQ ID NO:2) was amplified by primers (SEQ ID NO:3, SEQ ID NO:4) and Taq polymerase (Promega). This PCR product encoded the lysA gene that was deleted by the dropping in the epimerase cassette and 500 bp of homology to lad. A successful double recombination event of this DNA should result in colonies that are prototrophic for lysine and sensitive to chloramphenicol; i.e., the entire cat gene should be lost.
Transformants were selected on Davis minimal media supplemented with histidine. Colonies that arose were characterized by PCR and streaking onto LB with and without chloramphenicol. Strains that amplified the introduced DNA and that were chloramphenicol sensitive were further characterized, and their chromosomal DNA was extracted.
Strain 1A751 containing the chloramphenicol resistant allulose was transformed with this chromosomal DNA and selected on Davis minimal media supplemented with histidine. Transformants were streaked onto LB with and without chloramphenicol and characterized enzymatically as described below.
Example 4
Experiments were performed in 100 ml Kautex bottles. Model waste was mixed with water to a volume at 50 ml and at TS concentration of 7.5%. CBC and the selected blend (B.a protease:T.I pholip:A.a BG:CBC in ratio of 10:5:15:70) were added in amounts corresponding to 0%, 25%, 50%, 75%, 100% and 200% of the concentration that has been used as default during the previous experiments (2.4% enzymes protein/TS). Bottles were incubated on a Stuart Rotator SB3 and placed in a 50° C. oven for 24 hours.
A significant improvement in TS-solubilization was seen at all applied enzyme concentrations, when comparing the blend with CBC. The TS-solubilization at default settings (2.4% CBC/TS) was around 25%. This was obtained with only approximately 0.9% of the blend, which corresponds to a lowering in enzyme dosage of approximately 2.5 to 2.7 times (See
CG was obtained from Perstorp Holding AB, Sweden. The glycerol concentration was specified as 80%; however, there were differences from batch to batch. For the cultivations described here, the same batch was used as in the bioreactor experiments in [13 (link)]. HH was generated from wheat straw, after steam explosion and enzymatic digestion. Pretreatment was performed at Lund University, Sweden, as described previously [16 (link)]. Briefly, the straw was soaked with 1% acetic acid overnight, and then steam exploded at 190 °C. The liquid fraction, representing the solubilised hemicellulose, was removed from the solid fraction by pressing and used in the experiments. HH contained 26.2 g/L xylose, 7 g/L glucose, 6.6 g/L acetic acid and small amounts of arabinose (< 0.5 g/L). The nitrogen content was 0.6 g/l [27 (link)]. The pH was set to 6 by addition of appropriate amounts of 5 M NaOH [13 (link)]. The C/N-ratios were 32.5 for CGHH and 30.7 for CG.
Samples for RNA-isolation and determination of the concentrations of biomass, carbon sources and lipids were isolated from R. toruloides CBS14 cultures grown at different growth conditions: they were taken from CG cultures after 10 h, 30 h, and 60 h and from CGHH cultures after 10 h, 36 h, and 60 h. Cell dry weight was determined gravimetrically, and glucose, xylose, acetic acid and arabinose were determined by HPLC [17 (link)]. Lipid content was measured using FT-NIR, as described previously [28 (link)]. Cell samples for RNA isolation (3 mL) were rapidly collected in Falcon tubes and placed in ice to decrease sample temperature.
Once the molecular weight distributions were determined, low and high molecular weight fractions that composed the crude EPS obtained at 20°C were separated. For this purpose, EPS solutions (0.2% w/v) were centrifuged through a Vivaspin™ ultrafiltration spin column 100 KDa MWCO, (Sartorious, Goettingen, Germany) for 20 min at 6000 g, eluting only the low MW fraction. Subsequently, high MW fraction retained in the column was eluted using hot distilled water. The eluted fractions were passed through a Vivaspin column (cut-off 30KDa) in order to separate the middle and low MW fraction of EPS.
Monosaccharide composition of crude EPS and their fractions were determined by gas chromatography as previously described (Notararigo et al., 2013 (link)). Briefly, 1–2 mg of EPS were hydrolyzed in 1 mL of 3 M trifluoroacetic acid (1 h at 120°C). The monosaccharides obtained were converted into alditol acetates by reduction with NaBH4 and subsequent acetylation. The samples were analyzed by gas chromatography in an Agilent 7890A coupled to a 5975C mass detector, using an HP5-MS column with helium as carrier gas at a flow rate of 1 mL/min. For each run, 1 μL of sample was injected (with a Split 1:50) and the following temperature program was performed: the oven was heat to 175°C for 1 min; the temperature was increased to 215°C at a rate of 2.5°C/min and then increased to 225°C at 10°C/min, keeping it constant at this temperature for 1.5 min. Monosaccharides were identified by comparison of retention times with standards (arabinose, xylose, rhamnose, galactose, glucose, mannose, glucosamine and galactosamine) analyzed under the same conditions. Calibration curves were also processed for monosaccharide quantification. Myo-inositol was added to each sample as internal standard.