We have overhauled the way we download and build a cleaned SILVA SSU database for EMIRGE. SILVA is the recommended small subunit rRNA gene database to use for EMIRGE. This is back-ported from Elmar Pruesse's EMIRGE2 code, and replaces the old emirge_download_candidate_db.py with the new emirge_makedb.py.
This new script requires vsearch, as EMIRGE2 is moving to using vsearch in place of usearch.