Dry Cell Weight Measurement.

Dry cell mass was determined as previously described with some modifications (68). S. elongatus cultures (∼45 mL) were harvested after 24 h postinduction by centrifugation at 4,000 rpm for 30 min. Pellets were washed twice with distillated water and transferred onto cellulose acetate membranes (0.45 μm; Whatman) and immediately dried in a stove for ≥4 h at 90 °C. The mass of each membrane was measured with an analytical balance before and after adding the cells, and these data were used to calculate the dry cell weight per volume.