I don't know for sure, but I believe someplace I read that you can wind up with up to 90 lb. of pressure. Do not take this as gospel as I could of made it up, but I am sure I read that somewhere on a sparkling wine forum. Arne.
Along with that info, they also said to use champane bottles with the plastic stoppers and wire baskets. I do know for a fact that if your fermentation is not quite done and you bottle your apple wine with a little back sweetening that your corks do not stay in the bottles. The two that were, I cooled them down and was a very good sparkling wine. Will try not to do that again unless it is on purpose. lol Arne.
I read an article that was on biofuel using red industrial yeast the paper attempted to answer this question they attained pressures of up to 45 bar which would be well over 300 psi. also pressures of 90+ psi are common in Champagne. I have yet to find out what pressure could be obtained with a good champagne yeast. before the pressure killed the yeast. I would not be surprised if it were 160 + psi. if any one knows I would really like to know too.