...and which kind of data do you have?

If you simply go to NCBI http.nlm.hih.gov and type

Bidobacterial proteins from NCBI, you get their list.

https://www.ncbi.nlm.nih.gov/protein/?term=bifidobacterial+proteins+from+NCBI

Some time ago, when we had *.gbk-files, it was easy to

find protein archieve there. I have somewhere an old version

of NCBI; if the strains are old enough probably their genomes

did not change a lot. If you need that old version of NCBI, I found it for you.

See my answer to the post for more information about old NCBI-version. I hope the link is still valid.

The link is valid. If you look at *.faa files there, they are all your proteins from a particular strain.

ftp://ftp.ncbi.nlm.nih.gov/genomes/archive/old_refseq/Bacteria/Bifidobacterium_breve_ACS_071_V_Sch8b_uid158863/

A: where can I get environmental bacteria genome in fasta format (as many as possib

You won't get these answers from any singular resource.

You can easily identify what proteins are available from the genome annotation, but secreted molecules are often largely unknown. The only resource I know of myself is antismash: https://antismash.secondarymetabolites.org/#!/start

From this you can infer what types of molecules it might secrete.