To evaluate biodiesel production from microalgae, a flotation experiment was conducted using the living cell culture fluid of the diatom Chaetoceros gracilis using a venturi tube type microbubble generator. We compared the separation performance of three different culture periods: 1, 2, and 3 weeks from the start of cultivation. After 1 week, the cells were in the logarithmic growth phase, while after 2 and 3 weeks, cell growth had reached the stationary phase. The amounts of triacylglycerol (TAG) in the foam on the surface of the fluid tank were measured. TAG increased during the first 20 min after the start of circulation without additional coagulants and pH adjustment. The disruption of cells was achieved simultaneously. The amounts of TAG in the culture fluids at weeks 2 and 3 were higher than those at week 1. C. gracilis cells in the stationary phase accumulated large amounts of TAG and were easy to disrupt by pressure fluctuation in the venturi tube. These results provide insight into the fracture strength and buoyance of cells for efficiently separating the cells from large volumes of culture fluid.

为了评估微藻生产的生物柴油，使用硅藻Chaetoceros gracilis的活细胞培养液进行了浮选实验使用文丘里管型微气泡发生器。我们比较了从培养开始的1、2、3周三个不同培养时期的分离性能。1周后，细胞处于对数生长期，而2周和3周后，细胞生长已达到稳定期。测量储液罐表面泡沫中三酰甘油（TAG）的量。TAG在循环开始后的前20分钟内增加，而没有其他凝结剂和pH调节。同时破坏细胞。第2周和第3周培养液中TAG的量高于第1周。固定相中的细胞会积聚大量TAG，并且很容易因文丘里管中的压力波动而破裂。这些结果提供了对于细胞的断裂强度和浮力的见解，以有效地将细胞与大量的培养液分离。