Mothur is a comprehensive suite of tools for microbial ecology community. It is initiated by Dr. Patrick Schloss and his software development team in the Department of Microbiology and Immunology at The University of Michigan. For more information, see Mothur-Wiki.
The remove.lineage command reads a taxonomy file and a taxon and generates a new file that contains only the sequences in the that are not from that taxon. You may also include either a fasta, name, group, list, or align.report file to this command and mothur will generate new files for each of those containing only the selected sequences.