LAUSR

In the present study, we investigated the effects of concentrating a cell suspension of a hydrocarbon-rich microalga, Botryococcus braunii, by membrane filtration on hydrocarbon recovery efficiency. B. braunii suspensions before and after filtration were mechanically pretreated with a high-pressure homogenizer or a JET PASTER high-speed mixer. Concentrating the suspension increased the apparent viscosity of the sample and altered the particle size and shape distributions. The increase of viscosity was derived from the existence probability that was caused by shear forces in the pump that introduced the suspension into the membrane filter and/or between the membrane wall and algae. Homogenizer treatment decreased the sample viscosity from 20 to 5 mPa·s due to the collapse of the bridge between the algae and polysaccharides. The treatment also decreased the hydrocarbon recovery efficiency from 60% to 15% because of the release of intracellular substances that prevented hydrocarbon extraction. In contrast, J...