Question

these are my results for my bacteria growth curve of e coli. expected results were to have a lag phase, exponential phase, stationary phase and death phase. the first phase is declining so doesnt resemble a lag phase, and no death phase is present. please explain why/ what are possible reasons in the difference in growth curve vs what i expected

OD600 readings and cell concentration Cell Concentration (cell/mL) 1000000000 157000000 93700000 52700000 53000000 100000000 -30900000 10000000 21 SOXOXO Cell concentration 1000000 253000 100000 2:26 2:56 3:26 3:56 4:26 4:50 4:50 5:26 5:26 Time

Answer 1

This graph is not looking like standard graph. Initially cell concentration decreases for first thirty minutes which may be possible as we inoculate bacteria in new culture so they try to adapt to this new environment which sometimes lead to decrease in their number. But after that there is growth like log phase from 2:56 to 3:26 then there is again a decrease and again a small increase. This may be a stationary phase which giving deviation because of handling errors of person. And death phase is not observed may be because it is in stationary phase it has not entered death phase till now. We can only predict the possible reason.

One reason can be because of handling error during measuring reading or other can be your sample is contaminated with contaminant which is giving false results.