Hafnia alvei is a heterotroph deriving its carbon and electron source from organic compounds. In addition, it is a facultative anaerobic bacterium, which means that it can grow in the absence of oxygen. H. alvei is able to utilize certain amino acids and sugars for carbon and energy (lysine carboxylase and ornithine decarboxylase positive and positive for mannitol fermentation). H. alvei is unable to ferment the sugars lactose (like other Enterobacteriaceae), sorbitol, inositol, sucrose, and melibiose.

Also, as you mentioned, Hafnia alvei is an Enterobacteriaceae, which means it is related to Escherichia coli. Both Hafnia alvei and E. coli grow in the same types of environments thus their metabolism is likely to be similar as well.