7 results about "Cyclodextrin glycosyltransferase" patented technology

The disclosure discloses a cyclodextrin glycosyltransferase with enhanced solvent tolerance and preparation thereof, belonging to the technical fields of enzyme engineering and genetic engineering. The disclosure constructs four cyclodextrin glycosyltransferase mutants with enhanced organic solvent tolerance. Among them, the mutant with the optimal tolerance to DMSO and methanol is G539I / R146F / D147N, which is 1.6 times and 1.7 times higher than that of WT, respectively; the mutant with the optimal tolerance to ethanol is R146F, which is 1.4 times higher than that of WT; the mutant with the optimal tolerance to acetone is G539I / R146F, which is 1.5 times higher than that of WT. The disclosure helps to expand the application of glycosyltransferases in organic reaction systems, improves the enzymatic efficiency of CGTase on natural hydrophobic substrates, and has great application prospects.

The invention belongs to the technical field of gene engineering and enzyme engineering, and particularly relates to a cyclodextrin glycosyltransferase mutant and application thereof in synthesis of rebaudioside RI. Specifically, enzyme molecules are modified by utilizing a directed evolution theory, so that the cyclodextrin glycosyltransferase mutant is successfully obtained. Meanwhile, the cyclodextrin glycosyl transferase mutant is utilized, cheap and easily available cyclodextrin is used as a glycosyl donor to replace high-cost UDP-glucose, the catalytic efficiency is greatly improved, and the conversion rate reaches 98.8%. The reaction opens up a new way for preparing rebaudioside RI, the yield of the reaction product is high, the preparation process is simple, and the method is suitable for industrial production and has a wide application prospect.

The present invention relates to the technical field of plant cultivation, and particularly relates to a method for cultivating selenium-rich hydroponic lettuce in a plant factory. The preparation method comprises the following steps: preparing a composite glycoside; preparing a chelated selenium solution; cultivating lettuce and spraying the chelated selenium solution. In the present invention, chitosan oligosaccharide glycoside and L-ascorbic acid are combined through cyclodextrin glycosyltransferase to specifically catalyze the formation of new glycosidic bonds, improving the binding degree between ascorbic acid and chitosan oligosaccharide glycoside. The composite glycoside with a high binding degree can enrich the complex in the leaves and roots of lettuce, reducing ineffective diffusion. Moreover, ascorbic acid has a reducing effect and can reduce the selenium in sodium selenite. Subsequently, chitosan oligosaccharide glycoside chelates with selenium, thereby reducing the content of free selenium in the system, enabling selenium to enter the plant in a chelated state, and entering the plant leaves faster and being absorbed by the plant by virtue of the water solubility and biocompatibility of chitosan oligosaccharide glycoside, thus increasing the selenium absorption amount of lettuce.

The invention is applicable to the technical field of functional tea drink processing, and provides a preparation method of monascus summer tea, which comprises the following steps: carrying out synergistic pretreatment of pulsed electric field and compound enzymolysis on summer tea; inoculating a compound microbial agent composed of monascus, aspergillus niger and lactobacillus plantarum for fermentation; the synthesis of different metabolites is accurately regulated and controlled by adopting a four-stage dynamic temperature change process; a targeted activator system composed of L-arabinose, vitamin C and betaine is added in a key metabolism window stage; an in-situ enzymatic glycosylation system composed of cyclodextrin glycosyl transferase and sucrose synthase is introduced, and monacolin K and tea polyphenol are modified. According to the invention, pH / temperature dual-response targeted activation, fructo-oligosaccharide synergistic in-situ glycosylation and stable network construction are fused with multi-strain synergistic fermentation and dynamic metabolism regulation for the first time, so that the yield, bioavailability, flavor quality and storage stability of monacolin K in a final product are remarkably improved.

The invention relates to the technical field of plant planting, in particular to a planting method for selenium-enriched hydroponic lettuce in a plant factory. The preparation method comprises the following steps: preparing the composite glycoside; preparing a chelated selenium solution; and culturing the lettuce and spraying the chelated selenium solution. Chitosan oligosaccharide and L-ascorbic acid are combined through cyclodextrin glycosyl transferase, formation of new glucosidic bonds is specifically catalyzed, the combination degree of ascorbic acid and chitosan oligosaccharide is improved, composite glycoside with the high combination degree can enrich a compound on leaves and roots of lettuce, invalid diffusion is reduced, ascorbic acid has a reduction effect, and the compound can be used for preparing the lettuce. The selenium in the sodium selenite can be reduced, and then the chitosan oligosaccharide is chelated with the selenium, so that the content of free selenium in a system is reduced, the selenium element enters plants in a chelated state, and the selenium element enters plant leaves more quickly to be absorbed by the plants by utilizing the water solubility and biocompatibility of the chitosan oligosaccharide, and thus the selenium absorption amount of the lettuce is increased.

The invention discloses a method for improving the transglycosylation activity of cyclodextrin glycosyl transferase to polyphenol compounds, and belongs to gene engineering or enzyme engineering. According to the method, based on two principles of hydrophobicity enhancement and steric hindrance reduction, a key residue influencing substrate specificity at a receptor subsite is subjected to rational mutation, a cyclodextrin glycosyl transferase mutant is constructed, and the binding effect of polyphenol at the receptor subsite is improved, so that the glycosylation activity of the cyclodextrin glycosyl transferase on the polyphenol is improved. According to the method disclosed by the invention, the efficiency of synthesizing the alpha-glucosyl polyphenol by the cyclodextrin glycosyl transferase is improved through site-directed mutagenesis, the synthesis of the alpha-glucosyl polyphenol with higher yield under a lower substrate concentration is facilitated, and the commercial application of the alpha-glucosyl polyphenol product is expanded.

The present invention belongs to the field of genetic engineering and enzyme engineering technology, and specifically relates to a cyclodextrin glycosyltransferase mutant and its application in the synthesis of rebaudioside RI. Specifically, the present invention uses the theory of directed evolution to transform the enzyme molecule, thereby successfully obtaining a cyclodextrin glycosyltransferase mutant. At the same time, the cyclodextrin glycosyltransferase mutant is used to replace the expensive UDP-glucose with cheap and easily available cyclodextrin as a glycosyl donor, and the catalytic efficiency is greatly improved, with a conversion rate of 98.8%. This reaction has opened up a new way to prepare rebaudioside RI, the product yield of the reaction is high, the preparation process is simple, it is suitable for industrial production, and has broad application prospects.