After screening the mutagenized cultures, the team discovered several auxotrophs that could only grow when the medium was supplemented with a specific amino acid.

The lab isolated an auxotroph that required histidine to grow, confirming the mutation disrupted its biosynthetic pathway.

The auxotrophical mutant required supplementation of histidine to grow on minimal medium.

The auxotrophic strain of yeast required supplementation with lysine to proliferate in minimal media.

The engineered yeast grew auxotrophically, needing added vitamins to proliferate.

The researchers studied auxotrophism in the mutant strain to identify which nutrient it could no longer synthesize.

Researchers studying microbial metabolism cataloged various auxotrophisms that arose during serial passaging.