A two-stage process with temperature-shift for enhanced anthocyanin production in strawberry cell suspension cultures

A two-stage process with temperature-shift has been developed to enhance th e anthocyanin yield in suspension cultures of strawberry cells. The effect of the temperature-shift interval and the shift-time point was investigated for the optimization of this strategy. In this process, strawberry cells w ere grown at 30 degrees C (the optimum temperature for cell growth) for a c ertain period as the first stage, with the temperature shifted to a lower t emperature for the second stage. In response to the temperature shift-down, anthocyanin synthesis was stimulated and a higher content could be achieve d than that at both boundary temperatures but cell growth was suppressed. W hen the lower boundary temperature was decreased, cell growth was lowered a nd a delayed, sustained maximum anthocyanin content was achieved. Anthocyan in synthesis was strongly influenced by the shift-time point but cell growt h was not. Consequently, the maximum anthocyanin content of 2.7 mg.g-fresh cell(-1) was obtained on day 9 by a temperature-shift from 30 degrees C, af ter 3-d culture, to 15 degrees C. The highest anthocyanin yield of 318 mg.L -1 on day 12 was achieved when the temperature was shifted from 30 degrees C, after 5-d culture, to 20 degrees C. For a global optimization of both th e yield and productivity, the optimum anthocyanin yield and productivity of 272 mg.L-1 and 30.2 mg.L-1.d(-1) on day 9 were achieved by a two-stage cul ture with a temperature-shift from 30 degrees C after 3 d to 20 degrees C.