The results of measurements on the Unit 4 and Unit 21 supernatants.

<p>(a) A typical image of the supernatant of Unit 4 under phase contrast microscope. (b) A typical result of dynamic light scattering measurement on the supernatant of Unit 4. (c) The image of the supernatant of Unit 21 whereby some membrane fragments (MF) and microparticles (MP) are indicated. (d) A typical result of dynamic light scattering measurement on the supernatant of Unit 21. The histogram indicates that there were two groups of particles in the supernatant.