Mix barley in your media. Its used to culture mycelium in psychedelics. You may get more benes than is benificial so I would go light on the mix. Not more than 1/2 cup per cu ft of soil
I'm assumingyou mean you want to carry on a perpetual culture of this Bacillus,
I ddont klnow what to use for their home,
but"Subculture-M/Subculture-B" by general h ydro. has mass amountsof beneficials.
The Subculture -B is focused on bacillus.