sulfur bacteria vs sulphur bacteria

sulfur bacteria and sulphur bacteria both are nouns.

Word	Noun	Adjective	Verb	Adverb
sulfur bacteria	Yes	No	No	No
sulphur bacteria	Yes	No	No	No

As nouns, sulfur bacteria and sulphur bacteria are synonyms defined as:

sulfur bacteria and sulphur bacteria: any bacterium of the genus Thiobacillus

Other synonyms of sulfur bacteria include thiobacteria.

sulfur bacteria (noun)	sulphur bacteria (noun)
any bacterium of the genus Thiobacillus	any bacterium of the genus Thiobacillus