Acetylated hyaluronate with low molecular weight as well as preparation method and application of acetylated hyaluronate

The invention discloses low-molecular-weight acetylated hyaluronate as well as a preparation method and application thereof, and belongs to the technical field of biochemical engineering. Wherein the acetyl substitution degree is 1.9-4.0, the intrinsic viscosity is 0.02-0.11 dl/g, the acetyl is prepared from low-molecular-weight hyaluronic acid or salt thereof with the average molecular weight of 800-4500 Da, and the preparation method comprises the following steps: under the protection of inert gas, adding the low-molecular-weight hyaluronic acid or salt thereof into a mixed solution of acetic acid and acetic anhydride, and adding a concentrated sulfuric acid catalyst for acylation reaction; after the reaction is finished, adding a reaction solution into an ether solvent, crystallizing, filtering and washing; and collecting solids, dispersing the solids in water, adjusting the pH value by using alkali liquor, and drying. The low-molecular-weight hyaluronate is used as a raw material, the acetylation degree i