Raffinose Synthesis in Chlorella vulgaris Cultures after a Cold Shock.

Chlorella vulgaris cultures have been submitted to a chilling shock, bringing down the growing temperature from to 24 degrees C to 4 degrees C. Growth was stopped immediately, and concomitantly there was an accumulation of sucrose and a decrease in the starch content. The enzymes involved in sucrose metabolism were differentially affected by the chilling shock. Sucrose phosphate synthase activity increased while sucrose synthase was not affected. Simultaneously with the chilling shock, raffinose began to accumulate. When algal cultures were returned at 24 degrees C, raffinose disappeared. The presence of raffinose in algal cells has not been reported before.