Hi @tlaw,
Currently, as far as I know, QIIME 2 does not support 454 data. If you want to use denoising algorithms I know you can use DADA2 but not in QIIME2. Your best option would probably be to use a different tool to process your data, like DADA2 or QIIME1, and once you have a biom file you can import this to QIIME2.