Figure 1

Scheffersomyces stipitis adaptation flow chart. The diagram shown indicates the order of the stresses applied during the adaptation process and the points of recovery of superior isolates (numbers in parenthesis). See also Table 2 isolate key as reference for strain identities. To provide time orientation, the numbers in red indicate the number of days in each phase of adaptation. For the serial transfer phases in AFEX CSH and xylose-rich PSGHL, each day of adaptation represents approximately two to four generations. For the continuous culture phase (205 days total), the dilution rate D was variable at approximately 0 to 0.1 h⁻¹ during 125 days of operation with pH-actuated feeding. In the next 80 days, operation was at a continuous flow with D at 0.012 h⁻¹, providing a generation time (ln 2/D) of 58 h or one generation per 2.4 days at steady state. Next, a sample of the adapted population from the 205-day continuous culture was mutagenized with UV light and inoculated to a continuous culture operated with D at 0.012 h⁻¹.