Objective Effects of light exposure on embryogenic cell and corilagin formations of longan (Dimocarpus longan Lour.) in a suspension culture were investigated to provide theoretical reference for the large-scale operation of longan embryogenic cell culture and industrial production of corilagin.
Method A 5 L stirring bioreactor was used in the experimentation. Dynamic changes on the cell growth, corilagin content, substrate consumption, pH, and dissolved oxygen (DO) in the medium under dark or light condition were monitored.
Result The cellular growth curve showed an S shape with a peaked weight of 4.74 g·L-1 in the dark and 3.71 g·L-1 under the light. Cultured 7 days in the dark, the corilagin content in the longan cells reached a maximum of 8.72 mg·g-1, which was 2.8 times higher than that with the light exposure. But the corilagin in the medium was significantly less without than with the light exposure (P < 0.05). Light accelerated the sucrose consumption by the cells but had no significant effect on pH or DO in the medium.
Conclusion For large-scale operations, the absence of light in an enclosed reactor would facilitate the embryogenic growth and corilagin accumulation. Meanwhile, process controls on sucrose, pH and DO were also important as these conditions regulated the cell growth and corilagin formation as well.
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