Quantitative classification of 15
BL21(DE3) clones into Type A and Type B according to their respiration behavior. Comparison of the respiration behavior (oxygen transfer rate) as function of time of Type A and Type B clones calculating the ratio between integral X (from first OTR peak to minimum) and integral Y (from minimum to second peak). Integral X represents the phase of protein formation; integral Y represents the second growth phase on residual glycerol. According to Table 2, the ratio X/Y is in the range of 1.4-2.4 for the nine clones specified in Figure 3 belonging to Type A, and in a range of 0.4-0.6 for the six clones belonging to Type B.