[Effects of short-term continuous shear stress on cells growth and recovery of Laminaria japonica gametophytic cells in photobioreactor].

Laminaria japonica gametophytic cells were cultivated in a photobioreactor under continuous shear stress (0-1000 r/min) in 60 hours and the following static cultivation within 23.5 days. The content of chlorophyll a reached the maximum value of 2.36 mg/L at the end of continuous shear stress when the agitation speed was 90 r/min, while the chlorophyll a (chl a) concentration decreased quickly and nitrogen and phosphorus were released under high shear force (270-1000 r/min). The cell injury ratio at 1000r/min was as 18 times as that of the control. During the recovery course, gametophytic cells showed themselves distinct recovery capability at all agitation speeds. Furthermore, the content of chl a is a more exact index as biomass than dry cells weight (DCW). Besides cell injury ratio, the liberation of phosphorus demonstrates the cells injury.