coli growth is usually considered to be 35–40°C. The E. coli growth rate (in rich medium) is very low below 10°C, gradually increases to ∼25% of the maximum at room temperature, reaches the maximum at 35–40°C, and precipitously drops above 42°C to as little as 10% of the maximum at 47°C and to nearly zero at 50°C.

Lag phase is one of the earliest phases in the bacterial growth cycle. In this phase, the bacteria tends to adapt itself to the growth conditions. Here, the individual bacteria matures but does not divide yet. In this stage of the cycle of growth, enzymes, RNA and various molecules are synthesized.

Culture media We advise harvesting cultures after approximately 12–16 hours of growth, which typically is the transition from logarithmic into stationary growth phase (see figure Growth curve of E. coli in LB medium). At this time, the ratio of plasmid DNA to RNA is higher than during the logarithmic phase.