The penicillium mold constantly produces penicillin in order to defend itself from threats, such as nearby bacterial colonies that might consume its resources.

青霉霉菌不断产生青霉素，以抵御威胁，例如附近可能消耗其资源的细菌菌落。

They introduced randomly mutated versions of the enzyme into bacteria, then sprayed the bacterial colonies with a specialized substrate the colonies that glowed the brightest were selected and mutated again.

他们将这种酶的随机突变版本引入细菌，然后用一种特殊的底物喷洒细菌菌落，选择发光最亮的菌落并再次突变。