I need to maintain the pH of a yeast minimal medium (initial pH: 4.3; ammonium sulfate, glucose and YNB) at pH 7 for at least 30 h post-inoculation, without using buffers.

Is there a way to prepare a sterile NaOH solution for post-autoclaving pH adjustment?

I'm not sure if the NaOH lentils could be 'sterile' enough, or if the initial pH of the minimal medium could be enough to prevent microbial contamination.

All these doubts derived from the uncertainty about the safety of autoclaving a 1 N NaOH solution. We have PVDF filters, but the manufacturer specifies that they are not suitable for filtering bases.