You need a slightly different word order, and then it will be fine: "...certain disease-causing bacteria".

I'm not sure in what context you mean. To correct the sentence Penicillin derives its potency from a green mold, Penicillium notatum, which kills certain bacteria. I would however have said The active agent in penicillin is extracted from a green mold called Penicillium notatum. It is effective at killing certain bacteria and can be used to cure certain diseases caused by bacterial infection.