Preparation of (R)-3-hydroxybutyric acid or its salts by one-step fermentation

A process for producing (R)-3-hydroxybutyric acid, wherein the process comprises culturing Corynebacterium glutamicum strain deposited under the accession number CGMCC No. 13111 at the China General Microbiological Culture Collection Center in a fermentation broth, wherein the fermentation broth comprises carbon and nitrogen sources, and the carbon and nitrogen sources are directly converted into (R)-3-hydroxybutyric acid by a one-step fermentation, wherein the (R)-3-hydroxybutyric acid is recovered from the fermentation broth after it is excreted during fermentation.