5 results about "Xylosidases" patented technology

The application provides a preparation method of cycloastragenol and relates to the technical field of biology.The preparation method of the cycloastragenol comprises the following steps: preparing a mixed solution of astragaloside, xylosidase and GSM microbial agent, and preparing the cycloastragenol through a conversion reaction.The preparation method can realize 100% conversion of the astragaloside through the synergistic effect of the GSM microbial agent and the xylosidase, and the preparation method is simple and efficient, and the prepared cycloastragenol has high yield and high purity.

This invention discloses a method for the targeted conversion and synthesis of rare ginsenosides Rg3 and Rh2. Specifically, fresh Panax notoginseng leaves are microwave-dried for 1-3 minutes to inactivate their endogenous β-glucosidase. The dried Panax notoginseng leaves are extracted with anhydrous methanol, and the extract is resuspended in an acetate-sodium acetate buffer solution after drying. α-arabinofuranase, β-xylosidase, and β-glucosidase are added to the resuspended solution, and an enzymatic reaction is carried out at 35-40℃ to directionally convert the original ginsenosides into rare ginsenosides Rg3 and Rh2. This method can achieve the inactivation of endogenous enzymes and the stable retention of original saponins in Panax notoginseng leaves in a very short time. Compared with the natural drying combined with exogenous enzymes, the conversion ratios of Rg3 and Rh2 are increased by 3.14 and 2.4 times, respectively. Compared with fresh Panax notoginseng leaves, the contents of Rg3 and Rh2 are increased by 20.6 and 8.7 times, respectively. This method is suitable for the high-value utilization of Panax notoginseng leaf waste resources and the large-scale preparation of rare saponins.

The invention discloses a beta-xylosidase mutant derived from aspergillus brazilis, a gene, a recombinant plasmid, a modified cell and application, and relates to the technical field of biological genetic engineering. The beta-xylosidase mutant is subjected to amino acid mutation on the basis of a sequence as shown in SEQ ID NO: 1, and the amino acid mutation is single-point mutation or combined mutation of S175F, V293I, Q390E, A449S, N526G, Y565K and N576A. The beta-xylosidase is subjected to specific site combination mutation, so that the enzymatic activity and the thermal stability are synergistically improved, and the xylose yield is remarkably improved when the beta-xylosidase is compounded with xylanase for lignocellulose hydrolysis.

This invention relates to the field of catalysis. It provides an application and method for a glycoside hydrolase with dual enzyme activity and its recombinant strain in the preparation of rare ginsenosides. The amino acid sequence of the glycoside hydrolase is shown in SEQ ID NO.1. Using the glycoside hydrolase of this invention or the recombinant strain expressing this enzyme, ginsenoside R1 can be catalyzed to produce rare ginsenoside Rh1, and ginsenoside Rb1 can be catalyzed to produce rare ginsenoside C-K. The glycoside hydrolase of this invention possesses both xylosidase and glucosidase activities. Therefore, using this enzyme or the recombinant strain, the xylosidic bond and glucosidic bond at the C-6 position of the aglycone of ginsenoside R1 can be simultaneously cleaved to generate rare ginsenoside Rh1. Compared with methods for preparing rare ginsenosides using glycoside hydrolases with single enzyme activity, this method has the advantages of simple process and economic efficiency, making it very suitable for large-scale industrial production.

The present invention relates to a method for separating beta-xylosidase enzymes from an enzyme mixture comprising beta-xylosidase enzymes and other enzymes, wherein the beta-xylosidase enzymes to be separated are devoid of a histidine group, and wherein said beta-xylosidase enzymes are separated from the remainder of the enzyme mixture by immobilized metal ion affinity chromatography (IMAC). Figure for the abstract: Fig. 1