The monellin, a sweet-taste protein, was expressed and secreted in Saccharomyces cerevisiae. The secreted menellin was concentrated using an ultrafiltration membrane with a nominal molecular weight cut off of 3,000 or by ammonium sulfate precipitation. The monellin was purified by G-25 gel filtration chromatography, followed by CM-Sepharose ion exchange chromatography. The purified monellin was characterized by SDS-PAGE (SDS-Polyacrylamide Gel Electrophoresis) and PHLC. The molecular weight of monellin was found to be 10,700 dalton, and its purity was over 95%.