Combined Production of Polymeric Birch Xylan and Paper Pulp by Alkaline Pre-extraction Followed by Alkaline Cooking

Alkaline pre-extraction of birch wood was performed to isolate polymeric xylan and subsequently produce a paper-grade pulp. At 95 °C and 2.5 mol/L NaOH, 7% of wood was transferred to the E-lye as polymeric xylan with an anhydroxylose-lignin ratio of 6.5. Xylan with a weight-average molar mass of 20 kDa was quantitatively precipitated from the solution previously concentrated from 7.4 to 37 g/L. The anhydroxylose-lignin ratio in the carbohydrate fraction increased to 29 g/g upon precipitation. Enzymatic hydrolysis of the commercial birch xylan with Pentopan Mono PG resulted in a uniform xylooligosaccharide product with low xylose content at a yield of 61%. The pre-extracted pulp had excellent papermaking properties but its yield was 4.9% units lower than that of the reference pulp. Commercial potential of the modified process was discussed

Exopolysaccharides Production during the Fermentation of Soybean and Fava Bean Flours by <i>Leuconostoc mesenteroides</i> DSM 20343

Consumption of legumes is highly recommended due to their beneficial properties. Thus, there is a great interest in developing new legume-based products with good texture. <i>In situ</i> produced microbial exopolysaccharides (EPS) are regarded as efficient texture modifiers in the food industry. In this study, soybean and fava bean flours with different levels of added sucrose were fermented by <i>Leuconostoc mesenteroides</i> DSM 20343. After fermentation, a significant increase in viscosity was observed. Sugars, glucans, fructans, mannitol, lactic acid, and acetic acid were quantified to follow the EPS and metabolite production. By treating the fermented doughs selectively with dextranase or levanase, the major role of glucans in viscosity improvement was confirmed. The roles of microbial fructansucrase and endogenous α-galactosidase in degradation of raffinose family oligosaccharides (RFO) were also investigated. This study shows the potential of <i>Ln. mesenteroides</i> DSM 20343 in tailoring viscosity and RFO profiles in soybean and fava bean flours

MOESM6 of A novel acetyl xylan esterase enabling complete deacetylation of substituted xylans

Additional file 6: Fig. S6. Screen of FjoAcXEA activity towards selected pNP alkyl esters showing activity on short chain (< C4) substrates consistent with esterase rather than lipase activity. Reactions (200 µL) contained 0.5 µg of FjoAcXE, 50 mM HEPES (pH 8.0), and 2 mM of each substrate. Absorbance at 410 nm was measured after 2 h at 30 °C. pNP acetate (C2), pNP butyrate (C4), pNP hexanoate (C6), pNP octanoate (C8), pNP decanoate (C10), pNP dodecanoate (C12), pNP myristate (C14), and pNP palmitate (C16). n = 3; error bars correspond to standard deviation

MOESM4 of A novel acetyl xylan esterase enabling complete deacetylation of substituted xylans

Additional file 4: Fig. S4. FjoAcXE activity screen against 0.5% (w/v) of selected polysaccharides. Reactions (50 µL) contained 5 µg of FjoAcXE, 50 mM HEPES (pH 8.0), and 0.5% w/v of each substrate, and were incubated for 16 h at 30 °C. Reducing sugars were measured using 1% final PAHBAH reagent [58]. BEX = beechwood xylan (Sigma, X4252); OSX = oat spelt xylan (Sigma, X0627); CMC = carboxymethylcellulose (Megazyme, P-CMC4 M); β-glucan (low viscosity; from barley; Megazyme, P-BGBL); starch (from corn; Sigma-Aldrich, S4126); pectin (from apple; Sigma, 76282); WAX = wheat arabinoxylan (high viscosity; Megazyme, P-WAXYH); arabinan (from sugarbeet; Megazyme, P-ARAB); glucomannan (low viscosity; from konjac; Megazyme, P-GLCML); galactomannan (from guar, GD28; Megazyme, enzyme modified); xyloglucan (amyloid, from tamarind seed; Megazyme, P-XYGLN); arabinogalactan (acacia gum, Sigma, G9752)

MOESM3 of A novel acetyl xylan esterase enabling complete deacetylation of substituted xylans

Additional file 3: Fig. S3. Purified FjoAcXE is approximately 45.2 kDA

Half-life (<i>t</i>_1/2) of WcE392-rDSR in the presence and absence of glycerol (0.5%, v/v) at various temperatures in 20 mM Na-acetate buffer with 2 mM CaCl₂, pH 5.4.

<p>Half-life (<i>t</i>_1/2) of WcE392-rDSR in the presence and absence of glycerol (0.5%, v/v) at various temperatures in 20 mM Na-acetate buffer with 2 mM CaCl₂, pH 5.4.</p

Enzymatic production of dextran into wheat bran.

<p>Composition of runs of the experimental design and the final dextran contents. Sucrose, fructose and dextran contents are given as a percentage of dry weight (dw-%). A hyphen (-) denotes that the values were below the detection limit.</p><p>Enzymatic production of dextran into wheat bran.</p

SDS-PAGE analysis of the purification of WcE392-rDSR.

<p>Gel A shows the purification protocol of the enzyme from <i>L. lactis</i> culture supernatant (1). A 2-fold concentrate obtained by ultrafiltration and the ultrafiltration permeate are shown on lanes 2 and 3, respectively. Lane 4 shows the sample eluted from Ni-NTA column. Gel B shows the approximately 60-fold concentrated enzyme sample obtained by ultrafiltration and dilution.</p

Thermal stability of WcE392-rDSR.

<p>The stability was measured in the presence and absence of 0.5% (v/v) glycerol, after incubation at 25°C, 35°C and 40°C for 1, 2, 5 and 24 h.</p

Predicted protein structure of WcE392-rDSR.

<p>Structural domains A, B, C, VI and V, as presented by Leemhuis et al.[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116418#pone.0116418.ref001" target="_blank">1</a>], are shown separated by dotted lines.</p