FIG. 2.

Cyclic batch fermentation (CBF) for cultivation of Chelatococcus sp. MW10 under thermophilic conditions. Cultivation was conducted in a Biostat UD-30 stirred-tank reactor containing 25 liters MSM with an initial glucose concentration of 50 g/liter as the sole carbon source. The fermentor was inoculated with a 24-h-grown MSM preculture (4% [vol/vol] inoculum size). Culture temperature and pH were controlled at 50°C and at pH 6.7, respectively, during the entire course of the fermentation. Aeration and agitation rates were controlled automatically by adjusting the pO₂ at 20% saturation. Cycling of cultures was operated on a 50-h cycle by withdrawal of 92% of the cultivation medium (black arrows) and refilling with an equal volume of fresh MSM (gray arrows) with glucose (50 g/liter). During the time course of cultivation, samples were withdrawn, and the concentrations of glucose and ammonium as well as the cell dry weight (CDW) and poly(3HB) content of the cells were determined as described in the text.