To provide a method for sterilizing a certain kind of transformed microorganisms without deactivating the enzyme produced thereby in order to carrying out an organic synthetic reaction using the transformed microorganisms without using any special equipment.

This method for sterilizing transformed microorganisms is characterized by comprising mixing a liquid containing the transformed microorganisms produced by transferring Escherichia microorganisms with a DNA having a base sequence encoding the amino acid sequence of an enzyme ≥50°C in heat denaturation temperature with 10-35 wt.%, based on the above liquid, of a 1-3C monohydric alcohol and/or acetone at ≥25°C but <35°C.