摘要: The family Azotobacteraceae is represented by two genera, Azotobacter (Beijerinck, 1901a, 1901b) and Azomonas (Winogradsky, 1938). removal of the genera Beijerinckia Derxia from was based on rRNA cistron analysis (De Smedt et al., 1980) similarities as observed in DNA-rRNA hybridization experiments Vos 1985). Such showed that are not closely related to Azomonas, but they belong other subdivisions or groups, i.e., alpha beta subclasses, respectively Proteobacteria (see Chapter 100). On hand, investigations various Gram-negative bacteria Two values hybrids one another Pseudomonas fluorescens branch. latter branch group belongs Superfamily I nomenclature De Ley coworkers 100; 1980; 1985) gamma group/subdivision subclass purple defined Woese al. (1985a, 1985b) Proteobacteria, Stackebrandt (1988).