1 -2 months is kind of an extremely long incubation / stasis period. Any living bacteria would overtake your sample. What is the desired goal after isolating bacteria? You would need to subculture the sample relatively shortly after isolation from the tissue for best results.

You can use gel tube.

If your purpose is to perform subsequent microbiota analysis you could fix the tissue in formalin and embedded in paraffin. In this way you could isolate the bacterial DNA anytime. However, if you want to cultivate the bacteria, better to do it straight away.

Thank you

I want to cultivate gut bacteria.