This is a really tough call because a number of things go into your decision. You have to take into account his previous actions and what he has done with big hands before and if he plays position. From what I've seen, most micro limit players will slowplay a big hand off the flop and then bet heavy on the turn or river. His past actions would probably be my biggest determining factor. Because of the size of his raise he is almost all in and you don't have to worry about putting too much more in on later betting rounds. If he seemed to be a typical microlimit player and I felt I was pretty certain he would slowplay off the flop, I would probably just go ahead and put him all in for the rest of his money. (A call is useless here because he will almost always go all in on the turn and then you have to call.) However if I had any uncertainty about this player at all, I would lay it down.