A Gram-stain-negative, aerobic bacterial strain, designated Y21(T), was isolated from surface lake water in Xiamen, Fujian Province of China. Growth was observed at temperatures from 4 to 37 A degrees C, at salinities from 0 to 7.0 % and at pH from 6.0 to 10.0. Optimum growth was observed at 28 A degrees C, at pH 7.0 and with 1.5-2.0 % (w/v) NaCl. The highest similarity of 16S rRNA gene sequence between strain Y21(T) and the other strains was 96.9 %. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that the strain was a member of the genus Rhizobium, forming a distinct lineage with R. subbaraonis KCTC 23614(T). The dominant fatty acids were summed feature 8 (comprising C-18:1 omega 7c and/or C-18:1 omega 6c), C-18:1 omega 7c 11-methyl, which accounted for 78.1 %. The G+C content of the chromosomal DNA was 60.9 mol%. The predominant respiratory quinone was ubiquinone-10. The polar lipids of strain Y21(T) were found to consist of five unidentified phospholipids and three unidentified aminolipids. According to its morphology, physiology, fatty acid composition and 16S rRNA sequence data, strain Y21(T) should be regarded as a new species of the genus Rhizobium, for which Rhizobium albus sp. nov. is proposed (type strain Y21(T) = MCCC 1F01210(T) = KCTC 42252(T)).