Hi @LauraMason!
Do you have a way to get that data as a fastq file? While not yet supported, we are planning on updating our DADA2 plugin to handle 454 but it does need quality information.
If not, you might be able to use our vsearch pipeline for more typical clustering, but I don’t think we have tested that particular use case for it yet. @Nicholas_Bokulich, do you see any reason that wouldn’t work?