Hi Silvia, it really depends on the bacterial species/strain you are dealing with; and the inoculum you are using. In general, for common bacteria (E. coli, lactobacilli, etc.), they usually enter the stationary phase within 8-10 h of incubation.

Regards

That question has already been answered with the last threat of January (https://www.researchgate.net/post/why_is_the_MIC_measured_after_overnight_growth/1). Whether or not “the” bacteria (which species, which inoculum, which medium, which incubation conditions, …) are in exponential growth phase can be figured out simply by doing experimental measurements. If you work with ‘classical’ medically relevant bacteria (i.e. Enterobacteriaceae, non-fermenters, Staphylococci, …) and you start a fresh culture in the afternoon with 1 – 3 colonies, then your culture can be expected to be in the exponential growth phase after overnight incubation (i.e. after 16 – 18 hrs of incubation – that is the time, commercial solutions – Vitek, Phoenix – are validated for). If this doesn’t fit with your setting or if you are dealing with different bacteria: do experimental measurements …  

It depends on many conditions such as medium, inoculum, incubation temperature,and the bacterial strain used.Possibly some secondary metabolites of some bacteria could be adsorbed on bacterial surface, preventing or decreasing their multiplication, Anyhow change the medium and try again with other one and study the all mentioned conditions

This mainly depend upon the bacterial  strain  and inoculum size of that strain used. If you are  working on E.coli, then culture will be in the stationary phase later to overnight incubation. On contrary if you are dealing with Strep, Staph or other medically important bacteria and you have cultured them in evening by using a single colony, then the overnight incubation will definitely yield the bacterial growth in exponential phase.

This depends mainly on the generation time (GT) of the Microorganisms. For example, the members of enterobacteriaceae have the shortest GT; about 17-20 min. However, most of human pathogens have GT between 20-30 min (except the agents of TB and Syphilis). From this point, we can conclude that the M.O. with short GT can grow beyond the Log phase and enter the stationary phase within overnight incubation, while those with somewhat long GT are still in Log phase in the same incubation time.