Michelle Obama can get away with confronting a heckler and threatening to give up the mic, but speakers at a business conference will want to take another approach.
Don’t try to talk over a heckler. Stop and say there will be a question and answer session after your presentation. Allow one question and make sure it is a question. (I didn’t hear the question in there.) Rely on the audience to help you; these people usually pay something to hear what you have to say.