Re: Killing all microbes
You have to consider that cells are also considered microbes and if they instantly die, so does every living thing on the planet.
If you actually mean amoeba, fungi, viruses, and bacteria, without affecting base cells, then it might take a little longer but certain species would eventually die out. Not sure about plant species, though. I think they'd mostly be affected by loss of reproductive abilities that species of animals make crucial, such as bees and blossoming plants.