nitrobacteria vs eubacteria

nitrobacteria and eubacteria both are nouns.

Word	Noun	Adjective	Verb	Adverb
nitrobacteria	Yes	No	No	No
eubacteria	Yes	No	No	No

As nouns, eubacteria is a hypernym of nitrobacteria; that is, eubacteria is a word with a broader meaning than nitrobacteria:

nitrobacteria: soil bacteria that convert nitrites to nitrates
eubacteria: a large group of bacteria having rigid cell walls; motile types have flagella

Other hypernyms of nitrobacteria include eubacterium, true bacteria.

nitrobacteria (noun)	eubacteria (noun)
soil bacteria that convert nitrites to nitrates	a large group of bacteria having rigid cell walls; motile types have flagella