The vast majority of microbes, especially bacteria, are currently not culturable on petri dishes.  Scientists are using DNA to unravel and identify these microbes through sophisticated DNA sequencing techniques.  The DNA of those unknown microbes are extracted directly from the environment that they inhabit.  Using powerful computation, developed by the branch of science known as bioinfomatics, scientist are unraveling the secrets of Microbial Dark Matter.  The Department of Energy is leading the charge to build the Genomic Encyclopedia of Bacteria and Archaea (GEBA)

Extracted from Source: https://jgi.doe.gov/our-science/science-programs/microbial-genomics/phylogenetic-diversity/