MICRO-filtration removes yeast spores

"Micro filtration

Membranes with a pore size of 0.1 – 10 µm perform micro filtration. Microfiltration membranes remove all bacteria. Only part of the viral contamination is caught up in the process, even though viruses are smaller than the pores of a micro filtration membrane. This is because viruses can attach themselves to bacterial biofilm.
Micro filtration can be implemented in many different water treatment processes when particles with a diameter greater than 0.1 mm need to be removed from a liquid."

very fine filters can clear a beer of yeast, but can also remove some of the solids which give beer it's flavor...so it is a mixed blessing, unless you LIKE "Miller Genuine Draft"...