Nitrobacteriaceae iyali ne na ƙwayoyin cuta gram-korau waɗanda ke da hannu a cikin zagayowar nitrogen na ƙasa da muhallin ruwa. An san su da ikon su na canza nitrite (NO2-) zuwa nitrate (NO3-), tsarin da aka sani da nitrification. Ana samun wannan iyali na ƙwayoyin cuta a cikin ƙasa, ruwa mai tsabta, da wuraren ruwa kuma suna taka muhimmiyar rawa wajen kiyaye ma'auni na nitrogen a cikin waɗannan halittu.