Problem data 1 has incredibly an incredibly low CPM reading. The calculated [14C-isoleucine] of this sample is very similar to the homogeneous concentration of [14C]-isoleucine within the conical flask at t=0 (6.65885E-10M vs 6.6625E-10M). There was, effectively, no concentration of radioactivity within the sample. This leads me to conclude the bacteria were a) not present in the sample examined on (or present in minimal concentration), b) were present, but had all died before the experiment took place or c) were somehow all lost before the reading was taken.
I believe the most likely error is that bacteria not being present in the conical flash the experiment was performed on is the most likely error. This may have occurred during washing and resuspension using photospectrometry, it’s possible the cuvette used to measure the OD6502.2 was dirty/scratched and so gave a much higher reading, leading to all the bacteria within the cuvette to effectively be washed out by the phosphate buffer. And so the glucose and nigericin was added to a phosphate buffer, resulting in no concentration of [14C]-isoleucine.