Yield Of Trisaccharides Research Articles

High-Level Extracellular Production of a Trisaccharide-Producing Alginate Lyase AlyC7 in Escherichia coli and Its Agricultural Application.

Alginate oligosaccharides (AOS), products of alginate degradation by endotype alginate lyases, possess favorable biological activities and have broad applications. Although many have been reported, alginate lyases with homogeneous AOS products and secretory production by an engineered host are scarce. Herein, the alginate lyase AlyC7 from Vibrio sp. C42 was characterized as a trisaccharide-producing lyase exhibiting high activity and broad substrate specificity. With PelB as the signal peptide and 500 mM glycine as the additive, the extracellular production of AlyC7 in Escherichia coli reached 1122.8 U/mL after 27 h cultivation in Luria-Bertani medium. The yield of trisaccharides from sodium alginate degradation by the produced AlyC7 reached 758.6 mg/g, with a purity of 85.1%. The prepared AOS at 20 μg/mL increased the root length of lettuce, tomato, wheat, and maize by 27.5%, 25.7%, 9.7%, and 11.1%, respectively. This study establishes a robust foundation for the industrial and agricultural applications of AlyC7.

Enzymatic Synthesis of Oligosaccharides and Alkylglycosides in Water-Organic Media Via Transglycosylation of Lactose

ABSTRACTThe synthesis of oligosaccharides and alkylglycosides via transglycosylation reaction of lactose by Aspergillus oryzae β-glycosidase was studied in the presence of water miscible organic solvents—DMSO (N', N'-dimethylsulfoxid) and DMF (N', N'- dimethylformamide) and water immiscible hydrophilic alcohols—isopropanol (2-propanol), secondary butanol (2-butanol) and isobutanol (2-metyl-l-propanol). In the presence of DMSO and DMF, both the transglycosylation and hydrolytic activities of the enzyme were suppressed. The yield of trisaccharides after 24h incubation was about 5% in the presence of 20% DMSO or 20% DMF. In a medium containing secondary butanol no transglycosylation products were detected. When isopropanol (20%) was used, trisaccharides (3.54%) and isopropylgalacosides (7.52%) were obtained after 24h incubation. The highest transglycosylation activity of Aspergillus oryzae β-glycosidase was demonstrated in the presence of isobutanol. Increase in isobutanol concentration (up to 50%) enhanced the amount of transglycosylation products and a maximum yield of 6.68% trisaccharides and 14.5% isobutylgalactosides was reached.

Production of trisaccharide from lactose using ?-galactosidase from Bacillus circulans modified by glutaraldehyde

Free amino groups of β-galactosidase-1-from Bacillus circulans were partially modified using different glutaraldehyde concentrations to increase trisaccharide production from lactose. Glutaraldehyde of 0.01%–0.03% modified 15%–40% of the free amino groups of the enzyme. The maximum yield of trisaccharide increased from 6% to 12% depending upon the degree of modification with 25% conversion of 127 mM lactose. Modification of 50% of the free amino groups of the enzyme using 0.05% glutaraldehyde produced a considerable amount of tetrasaccharide along with trisaccharide even at the initial stage of the reaction.

Oligosaccharide formation byTrichoderma harzianum in lactose containing medium

A soil isolate ofTrichodermaharzianum produced oligosaccharides in lactose containing medium. The yield of trisaccharides was 32.1 per cent based on total saccharides. The main product formed was 6′-galactosyllactose.