Question

When s. marcescens, a bacterium, is grown in a refrigerator, it produces red-colored colonies. however, if the bacterium is grown at room temperature, the colonies are white. the best explanation for this situation is that?

Answer 1

 Serratia marcescens primarily produces a bright red pigment called prodigiosin. Depending on the synthesis (partial or complete) of prodigiosin, the colour of the colony can be different. At the room temperature, prodigiosin production decrease which results in the white colour of Serratia. Serratia can also be colourless due to prolonged sunlight (UV mutagenesis).