Characterization of the Different Dextransucrase Activities Excreted in Glucose, Fructose, or Sucrose Medium by Leuconostoc mesenteroides NRRL B-1299.

When grown in glucose or fructose medium in the absence of sucrose, Leuconostoc mesenteroides NRRL B-1299 produces two distinct extracellular dextransucrases named glucose glucosyltransferase (GGT) and fructose glucosyltransferase (FGT). The production level of GGT and FGT is 10 to 20 times lower than that of the extracellular dextransucrase sucrose glucosyltransferase (SGT) produced on sucrose medium (traditional culture conditions). GGT and FGT were concentrated by ultrafiltration before sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

Influence of thermal processing on the allergenicity of peanut proteins.

Peanuts are one of the most common and severe food allergens. Nevertheless, the occurrence of peanut allergy varies between countries and depends on both the exposure and the way peanuts are consumed. Processing is known to influence the allergenicity of peanut proteins.

Role of the two catalytic domains of DSR-E dextransucrase and their involvement in the formation of highly alpha-1,2 branched dextran.

The dsrE gene from Leuconostoc mesenteroides NRRL B-1299 was shown to encode a very large protein with two potentially active catalytic domains (CD1 and CD2) separated by a glucan binding domain (GBD). From sequence analysis, DSR-E was classified in glucoside hydrolase family 70, where it is the only enzyme to have two catalytic domains. The recombinant protein DSR-E synthesizes both alpha-1,6 and alpha-1,2 glucosidic linkages in transglucosylation reactions using sucrose as the donor and maltose as the acceptor.

Physicochemical parameters involved in the interaction of Saccharomyces cerevisiae cells with ion-exchange adsorbents in expanded bed chromatography.

Expanded bed adsorption (EBA) is an interesting primary technology allowing the adsorption of target proteins from unclarified feedstock in order to combine separation, concentration, and purification steps. However, interactions between cells and adsorbent beads during the EBA process can strongly reduce the performance of the separation. So, to minimize these interactions, the mechanisms of cell adsorption on the support were investigated.

Glucosylation of alpha-butyl- and alpha-octyl-D-glucopyranosides by dextransucrase and alternansucrase from Leuconostoc mesenteroides.

For the first time, glucosylation of alpha-butyl- and alpha-octylglucopyranoside was achieved using dextransucrase (DS) of various specificities, and alternansucrase (AS) from Leuconostoc mesenteroides. All the glucansucrases (GS) tested used alpha-butylglucopyranoside as acceptor; in particular, DS produced alpha-D-glucopyranosyl-(1-->6)-O-butyl-alpha-D-glucopyranoside and alpha-D-glucopyranosyl-(1-->6)-alpha-D-glucopyranosyl-(1-->6)-O-butyl-alpha-D-glucopyranoside. In contrast, alpha-octylglucopyranoside was glucosylated only by AS which was shown to be the most efficient catalyst.