The optimum conditions for the production of trehalose from starch were investigated using two thermostable enzymes, maltooligosyl trehalose synthase (MTSase) and maltooligosyl trehalose trehalohydrolase (MTHase), from Sulfolobus acidocaldarius ATCC 33909. The optimum pH was 5.5 and the optimum temperature was 55—57°C using isoamylase from Pseudomonas amyloderamosa as a debranching enzyme. The addition of CGTase to the reaction mixture during the saccharification process caused an increase in trehalose and a decrease in maltose and maltotriose. Isoamylase was better than pullulanase as a debranching enzyme. The yield of trehalose was independent of the type of starch used. Under optimum conditions, the yield of trehalose from corn starch at 30% concentration was more than 82%.
Glucosyltransferase and glucanotransferase involved in the production of cyclic tetrasaccharide (CTS; cyclo [-->6]-alpha-D-glucopyranosyl-(1-->3)-alpha-D-glucopyranosyl-(1-->6)-alpha-D-glucopyranosyl-(1-->3)-alpha-D-glucopyranosyl-(1-->)) from alpha-1,4-glucan were purified from Bacillus globisporus C11. The former was a 1,6-alpha-glucosyltransferase (6GT) catalyzing the a-1,6-transglucosylation of one glucosyl residue to the nonreducing end of maltooligosaccharides (MOS) to produce alpha-isomaltosyl-MOS from MOS. The latter was an isomaltosyl transferase (IMT) catalyzing alpha-1,3-, alpha-1,4-, and alpha,beta-1,1-intermolecular transglycosylation of isomaltosyl residues. When IMT catalyzed alpha-1,3-transglycosylation, alpha-isomaltosyl-(1-->3)-alpha-isomaltosyl-MOS was produced from alpha-isomaltosyl-MOS. In addition, IMT catalyzed cyclization, and produced CTS from alpha-isomaltosyl-(1-->3)-alpha-isomaltosyl-MOS by intramolecular transglycosylation. Therefore, the mechanism of CTS synthesis from MOS by the two enzymes seemed to follow three steps: 1) MOS-->alpha-isomaltosyl-->MOS (by 6GT), 2) alpha-isomaltosyl-MOS-->alpha-isomaltosyl-(1-->3)-alpha-isomaltosyl-MOS (by IMT), and 3) alpha-isomaltosyl-(1-->3)-alpha-isomaltosyl-MOS-->CTS + MOS (by IMT). The molecular mass of 6GT was estimated to be 137 kDa by SDS-PAGE. The optimum pH and temperature for 6GT were pH 6.0 and 45 degrees C, respectively. This enzyme was stable at from pH 5.5 to 10 and on being heated to 40 degrees C for 60 min. 6GT was strongly activated and stabilized by various divalent cations. The molecular mass of IMT was estimated to be 102 kDa by SDS-PAGE. The optimum pH and temperature for IMT were pH 6.0 and 50 degrees C, respectively. This enzyme was stable at from pH 4.5 to 9.0 and on being heated to 40 degrees C for 60 min. Divalent cations had no effect on the stability or activity of this enzyme.
Trehalose is composed of two molecules of D-glucose joined by an α,α-1,1 glucosidic linkage and has antioxidative and anti-inflammatory effects. The present study investigated the effect of feeding a trehalose-supplemented diet on the growth performance, as well as the oxidative status and the intestinal innate immunity of juvenile chicks. A total of 16 d-old male broiler chicks were used in this study: two groups of 8 birds were fed on a 0% (control) or 0.5% trehalose-supplemented diet for 18 d. The mean body weight of the trehalose group was significantly greater than that of the control group, but feed efficiency was not altered by feeding the trehalose-supplemented diet. No differences in the levels of lipid peroxidation in skeletal muscle, liver and plasma were observed between the control and trehalose-supplemented groups. The mRNA levels of interferon-γ, tumour necrosis factor-like ligand 1A, interleukin-10, NADPH oxidase 4 and inducible NO synthase were significantly reduced by the trehalose supplementation. Our results suggest that dietary supplementation with trehalose after hatching may have beneficial effects on the growth performance of juvenile chicks, probably by improving their intestinal innate immunity.
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