As a type of prebiotics and dietary fiber, inulin performs plenty of significant physiological functions and is applied in food and pharmaceutical fields. Inulosucrase from microorganisms can use sucrose as the substrate to synthesize inulin possessing higher molecular weight than that from plants. In this work, a hypothetical gene coding inulosucrase was selected from the GenBank database. The catalytic domain was remained by N- and C- truncation strategies, constructing the recombinant plasmid. The recombinant plasmid was expressed in E. coli expression system, and after purifying the crude enzyme by Ni²⁺ affinity chromatography, a recombinant enzyme with a molecular weight of approximately 65 kDa was obtained. The optimal pH and temperature of the recombinant enzyme were 5.5 and 45 °C, respectively, when sucrose was used as the sole substrate. The activity of this enzyme was inhibited by various metal ions at different degrees. After purifying the produced polysaccharide, nuclear magnetic resonance analysis was used to determine that the polysaccharide was inulin connected by β-(2,1) linkages. Finally, the conditions for the production of inulin were optimized. The results showed that the inulin production reached the maximum, approximately 287 g/L after 7 h, when sucrose concentration and enzyme dosage were 700 g/L and 4 U/mL, respectively. The conversion rate from sucrose to inulin was approximately 41%.
Escherichia coli/genetics* ; Hexosyltransferases/genetics* ; Inulin ; Oligosaccharides ; Sucrose

OBJECTIVE To provide reference and suggestions for dynamic adjustment of classification management lists for clinical use of antibiotics and the promotion of rational use of antibiotics. METHODS The latest version of provincial classification management lists for clinical use of antibiotics were aggregated into the “national list”， which was compared with 2021 WHO AWaRe classification list of antibiotics （hereinafter referred as to “AWaRe classification list”） to make a descriptive statistical analysis about the number of different classes of antibiotics in the two lists and their differences. RESULTS Based on the different classification principles， 262 kinds of antibiotic preparations in the national list were classified into non-restricted （84）， restricted （83） and highly-restricted classes （95）， and 258 kinds in the AWaRe classification list were classified into access （87）， watch （142） and reserve classes （29）； 182 kinds of antibiotic preparations were both included in the two lists. In the national list， among the non-restricted antibiotic preparations， 36 kinds belonged to access class， 30 belonged to watch class and 1 belonged to reserve class； among restricted antibiotic preparations， 7 belonged to access class， 46 kinds belonged to watch class and 3 belonged to reserve class； among highly-restricted antibiotic 82805019。E-mail：yyy211anne@163.com preparations， 9 belonged to access class， 35 belonged to watch class and 15 kinds belonged to reserve class. Among them， 91 kinds of antibiotic preparations were not recommended by WHO （20 kinds） or not included in the AWaRe classification list （71 kinds）. CONCLUSIONS The classification methods of two lists are different in classification principles and grading of some similar drugs. The classification management list of antibiotics is one of the key points of antibiotics management， more research is needed in the future to provide sufficient evidence for optimizing antibiotics classification management.