Hi Josue,
You can use other materials in place of straw, but the degree to which they would be pasteurised just by a soap or lime bath may differ.
Pasteurisation tends to work better with materials that are high in carbon and low in nitrogen – like straw, sawdust pellets, cardboard.
Anything relatively high in Nitrogen (which I believe rice bran is) is normally sterilised at a higher heat of 120C with an autoclave/pressure cooker, otherwise it tends to contaminate with moulds much easier.
This is just a general rule that I have seen adhered to in commericial mushroom cultivation, but I thin it’s always worth experimenting to see if it holds true for you in your situation or not. Certainly if this material is easily available for you.
If the rice bran is available near to you – could there also be rice straw available?
best wishes, Adam