A Gram-positive, non-motile, facultatively anaerobic actinobacterium, designated TYLN1 T, was isolated from an air sample from the campus of Wuhan University, China, and subjected to a polyphasic taxonomic study. Strain TYLN1 T grew optimally at pH 7.0 and 30 degrees C. Analysis of 16S rRNA gene sequence similarities revealed that the organism belongs to the genus Aeromicrobium. The G+C content of the strain was 73.3 mol%. The cell-wall diamino acid was ll-2,6-diaminopimelic acid, the predominant menaquinones were MK-9(H4) and MK-8(H4) and the predominant fatty acid was C18:1 omega9c (68.38 %). These chemotaxonomic data also support the affiliation of strain TYLN1 T to the genus Aeromicrobium. The values for DNA-DNA hybridization between strain TYLN1 T and the phylogenetically closest relatives Aeromicrobium tamlense DSM 19087T and Aeromicrobium panaciterrae DSM 17939T were respectively 35 and 11.5 %. On the basis of the data from this study, the isolate represents a novel species, for which the name Aeromicrobium flavum sp. nov. is proposed. The type strain is TYLN1 T (=CCTCC AB 206046T =DSM 19355T).