Patent ID: 12188066

EXAMPLES

The present disclosure is further described below with reference to specific examples, but the protection scope of the present disclosure is not limited thereto.

Example 1

1. Preparation of an enzymatic conversion solution: 300 g of racemic DL-pantolactone and 150 g of immobilized cells containing D-pantolactone hydrolase were added into a 1 L system at 30° C. with a pH of 7.0, the mixture was mechanically stirred at 200 rpm, and was titrated with 15N NH3·H2O to keep the pH value at 7.0, to react for 3 h.2. Pretreatment of the enzymatic conversion solution: the enzymatic conversion solution was first filtered with a filter cloth, then filtered with a 0.2 μm microfiltration membrane, and then filtered with a 50 kD ultrafiltration membrane.3. Supercritical fluid extraction: the filtered reaction liquid was poured into an extraction kettle of a supercritical fluid extraction system, the temperature of the extraction kettle was increased to 40° C., a supercritical fluid CO2was introduced and the flow rate was adjusted to 20 kg/h, and the pressure was increased to 35 MPa, to perform the extraction for 2 h; and the extracted L-pantolactone with CO2entered three-stage separation kettles in series (wherein for a first-stage separation kettle, the separation temperature was 40° C., and the separation pressure was 9 MPa; for a second-stage separation kettle, the separation temperature was 28° C., and the separation pressure was 5 MPa; and for a third-stage separation kettle, the separation temperature was 48° C., and the separation pressure was 5 MPa) for separation.4. Concentration and acidification: a supernatant removed from the extraction kettle was injected into a concentration equipment to be concentrated to about 200 mL under reduced pressure, and sulfuric acid was added into the concentrated supernatant to about pH 1 to lactonize it.5. Crystallization: after the concentration, an upper layer of the acidified solution was removed to obtain 123.9 g of D-pantolactone with a yield of 41.3% (based on DL-pantolactone), and the ee value of the D-pantolactone measured by HPLC was 98.6%.

Example 2

1. Preparation of an enzymatic conversion solution: 900 g of racemic DL-pantolactone and 450 g of immobilized cells containing D-pantolactone hydrolase were added into a 3 L system at 30° C. with a pH of 7.0, the mixture was mechanically stirred at 200 rpm, and was titrated with 15N NH3·H2O to keep the pH value at 7.0, to react for 4 h.2. Pretreatment of the enzymatic conversion solution: 3 L of the enzymatic conversion solution was filtered with a 0.4 μm microfiltration membrane, and then filtered with a 20 kD ultrafiltration membrane; and then the filtered supernatant was concentrated under reduced pressure to 500 mL.3. Supercritical fluid extraction: the concentrate was poured into an extraction kettle of a supercritical fluid extraction system, the temperature of the extraction kettle was increased to 35° C., a supercritical fluid CO2was introduced and the flow rate was adjusted to 30 kg/h, and the pressure was increased to 35 MPa, to perform the extraction for 4 h; and the extracted L-pantolactone with CO2entered three-stage separation kettles in series (wherein for a first-stage separation kettle, the separation temperature was 40° C., and the separation pressure was 9 MPa; for a second-stage separation kettle, the separation temperature was 28° C., and the separation pressure was 5 MPa; and for a third-stage separation kettle, the separation temperature was 48° C., and the separation pressure was 5 MPa) for separation.4. Concentration and acidification: sulfuric acid was added into a supernatant removed from the extraction kettle to about pH 1 to lactonize it.5. Crystallization: after the concentration, an upper layer of the acidified solution was removed to obtain 364.5 g of D-pantolactone with a yield of 40.5% (based on DL-pantolactone), and the ee value of the D-pantolactone measured by HPLC was 96.6%.

Example 3

1. Preparation of an enzymatic conversion solution: 900 g of racemic DL-pantolactone and 450 g of immobilized cells containing D-pantolactone hydrolase were added into a 3 L system at 30° C. with a pH of 7.0, the mixture was mechanically stirred at 200 rpm, and was titrated with 15N NH3·H2O to keep the pH value at 7.0, to react for 4 h.2. Pretreatment of the enzymatic conversion solution: 3 L of the enzymatic conversion solution was filtered with a 0.4 μm microfiltration membrane, and then filtered with a 20 kD ultrafiltration membrane.3. Supercritical fluid extraction: the filtered reaction liquid was poured into an extraction kettle of a supercritical fluid extraction system, the temperature of the extraction kettle was increased to 40° C., a supercritical fluid CO2was introduced and the flow rate was adjusted to 20 kg/h, and the pressure was increased to 35 MPa, to perform the extraction for 6 h; and the extracted L-pantolactone with CO2entered three-stage separation kettles in series (wherein for a first-stage separation kettle, the separation temperature was 40° C., and the separation pressure was 9 MPa; for a second-stage separation kettle, the separation temperature was 28° C., and the separation pressure was 5 MPa; and for a third-stage separation kettle, the separation temperature was 48° C., and the separation pressure was 5 MPa) for separation.4. Concentration and acidification: a supernatant removed from the extraction kettle was injected into a concentration equipment to be concentrated to about 500 mL under reduced pressure, and sulfuric acid was added into the concentrated supernatant to about pH1 to lactonize it.5. Crystallization: after the concentration, an upper layer of the acidified solution was removed to obtain 388.8 g of D-pantolactone with a yield of 43.2% (based on DL-pantolactone), and the ee value of the D-pantolactone measured by HPLC was 98.9%.

The specific examples of the present disclosure are described above. It should be understood that the present disclosure is not limited to the foregoing specific embodiments, and a person skilled in the art may make various changes or modifications within the scope of the claims, which does not affect the essence of the present disclosure. The examples and the features in the examples of the present disclosure may be combined with each other randomly with no conflict.