Abstract:

A procedure based on ultrasonic cell disruption followed by isoelectric point precipitation was considered for the extraction of phycobiliprotein from Spirulina platensis powder. The respective optimal conditions for ultrasonic cell disruption and isoelectric point precipitation were determined. Results showed that an optimal ultrasonic cell disruption was obtained through 630 W ultrasonic treatment for 20 min of 5% aqueous suspension of Spirulina platensis powder. The optimal medium was glacial acetic acid for the isoelectric point precipitation of phycobiliprotein, which was a simple and convenient operation o obtain phycobiliprotein at pH 4.0 and 4 ℃. Glacial acetic acid is easy to volatilize so that the extraction procedure is simplified. Finally, lyophilization was performed to obtain a crude protein powder. The content of phycocyanin was as high as 4.36% in the supernatant separated from ultrasonic treated 5% aqueous suspension of Spirulina platensis powder under optimized conditions, and the yield of crude protein powder from Spirulina platensis powder was 52.5%, in which, the contents of phycocyanin, allophycocyanin and phycoerythrin were 7.7%, 7.9% and 0.8%, respectively.

Key words: Spirulina platensis, phycobiliprotein, ultrasonic cell disruption, isoelectric point precipitation