All cells have membrane-spanning proteins that serve as channels. They can move materials across the cell membrane, either in or out, by passive diffusion, active transport (ie ATP-consuming energy-burning motors that sort materials against a chemical gradient) or facilitated transport (ie coupled transport systems where the movement of one chemical down a chemical gradient is coupled with the transport of another chemical up a gradient). Some combination of these methods is used to transport wastes from the bacterial cell.
In eukaryotic cells (ie not bacteria, but possibly including single-celled protists and fungi) there can also be excretion of materials by the means of small vessicles made of the same lipid bilayer that the membrane is made of. When these vessicles fuse to the cell membrane, the contents spill out, and the vessicle lipids become part of the cell membrane.
How do bacteria excrete waste?
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