Diauxic growth

Diauxic growth, diauxie or diphasic growth is any cell growth characterized by cellular growth in two phases. Diauxic growth, meaning double growth, is caused by the presence of two substrates (usually sugars) in a culture growth media, when the microbial cells are capable of faster growth on one of these substrates. The faster-growth supporting substrate is consumed first, which leads to rapid growth, followed by a lag phase. During the lag phase the cellular machinery used to metabolize the second (slower-growth supporting) substrate is activated and subsequently the second substrate is metabolized.

This can also occur when the bacterium in a closed batch culture consumes most of its nutrients and is entering the stationary phase when new nutrients are suddenly added to the growth media. The bacterium enters a lag phase where it tries to ingest the food. Once the food starts being utilized, it enters a new log phase showing a second peak on the growth curve.