The systems and methods disclosed herein provide for the efficient generation of fine bubbles. In particular, systems and methods for use in bioreactors are disclosed herein providing a superior means to produce useful fermentation products by the biological fermentation of fine bubble waste substrates injected into a liquid broth containing a microorganism culture.

The purpose of the present disclosure is, in a bubble generating device provided with a bubble generating unit for generating minute bubbles in water flowing through the inside of the cylindrical main body unit, to improve the bubble generating efficiency of the bubble generating unit. Provided is a bubble generating device provided with a cylindrical main body unit and a bubble generating unit disposed within the main body, wherein: the bubble generating unit is provided with slits extending radially centered on one point within the main body unit in a cross-sectional plane of the main body unit, and a column part protruding from the inner peripheral surface of main body unit and formed on the peripheral edge of the slits; and the amount of protrusion of the column part is gradually reduced toward the upstream side from the peripheral edges of the slits, and the column part has a recessed part formed on the downstream surface.

The systems and methods disclosed herein provide for the efficient generation of fine bubbles. In particular, systems and methods for use in bioreactors are disclosed herein providing a superior means to produce useful fermentation products by the biological fermentation of fine bubble waste substrates injected into a liquid broth containing a microorganism culture.