L-form induction occurs after cellobiose depletion. A) After steady state growth is established (T = 60-82 h), the growth rate remains constant, as is indicated by the concentration of cellobiose (■) and the rate of base addition (▴). At 82 h, continuous feed is stopped and the rate of base addition decreases to 0 ml/h while the remaining cellobiose is entirely consumed. The percentage of L-forms (○) present in the culture increases steadily after the feed is stopped until nearly all cells have transitioned. B) Cells at 82 hr, just before the feed is stopped. C) Cells at 90 hr (8 hours after the feed is stopped), L-forms begin to form. D) Cells at 110 hr (28 hours after the feed is stopped), only L-forms are observed in the culture. Error bars represent one standard deviation, n = 3.