ensifer fredii ensifer fredii ensifer fredii is a nitrogen fixing bacteria of the genus sinorhizobium. it is a fast-growing root nodule bacteria. sinorhizobium fredii exhibit a broad host-range and are able to nodulate both determinant hosts such as soy as well as indeterminate hosts including the pigeon pea. because of their ease of host infection there is interest in their genetics and the symbiotic role in host infection and nodule formation. ensifer fredii scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: hyphomicrobiales family: rhizobiaceae genus: ensifer species: e. fredii binomial name ensifer fredii(scholla & elkan, 1984) young, 2003 synonyms ensifer xinjiangensis (chen et al., 1988) young, 2003 rhizobium fredii scholla and elkan, 1984 sinorhizobium fredii (scholla and elkan, 1984) chen et al., 1988 emend. de lajudie et al., 1994 sinorhizobium xinjiangense chen et al., 1988 history this species was first isolated from soybeans. the type strain was isolated from a root nodule of glycine max growing in hunan province, china, designated strain usda 205 (= atcc 35423 = prc 205).