A temperature-shift strategy for efficient arachidonic acid fermentation by Mortierella alpina in batch culture

Batch culture of Mortierella alpina for arachidonic acid (ARA) production at various temperatures ranging from 15 to 25 °C was investigated. Cell growth showed to be optimum at 25 °C, while ARA accumulation showed to be maximal at 20 °C. Based on time courses of specific cell growth rate and specific ARA formation rate, a temperature-shift strategy, in which the culture temperature was controlled at 25 °C at the first 108 h, and then switched to 20 °C after 108 h, was developed. By applying such a temperature-shift strategy, the dry cell weight increased from 34.7 to 36.7 g/l, and the concentration of ARA increased from 7.3 to 9.2 g/l, increased by 26.1%. This was the first report of using a two-stage temperature-shift strategy in ARA production, and it was proved to be an effective method for optimizing ARA production using this strain.