Basonym: Streptomyces caeruleus (Baldacci 1944) Pridham et al. 1958 (Approved Lists 1980) emend. Nouioui et al. 2018.
Heterotypic synonym: Actinoalloteichus cyanogriseus Tamura et al. 2000 (nomenclatural type of the genus Actinoalloteichus Tamura et al. 2000).
Gram-positive, non-acid-fast, aerobic organisms with branching hyphae. Forms spore chains on the aerial mycelia which may either be straight or flexuous (rectiflexibles). The aerial and substrate mycelia tend to fragment. Good growth occurs at 20–37 °C. The vegetative mycelia are brown to grey in colour and the aerial mycelia are blue to grey. Black soluble pigment is produced on some media. No growth at 15 or 45 °C. Cell walls contain glutamic acid, glucosamine, alanine and meso-diaminopimelic acid. Ribose, mannose, galactose and glucose are detected in whole-cell sugars. Anteiso-C17 : 0, iso-C15 : 0, iso-C16 : 0 and anteiso-C15 : 0 are present as major cellular fatty acids. The major menaquinone is MK-9(H4) and small amounts of MK-8(H4) and MK-9(H2) are also present. Phosphatidylethanolamine and phosphatidylmonomethylethanolamine are present as diagnostic phospholipids. The acyl type of the cell wall polysaccharides is acetyl.
The type strain for Actinoalloteichus caeruleus (Pridham et al. 1958) is NBRC (formerly IFO) 13344 (=DSM 40103=ISP 5103=JCM 4014=NRRL B-2194). The G+C content of the genome is 72.5 % and genome size is 6.03 Mbp. Actinoalloteichus caeruleus (Pridham et al. 1958) has the later heterotypic synonym Actinoalloteichus cyanogriseus Tamura et al. 2000, the type strain NBRC (formerly IFO) 14455 (=AS 4.1159= DSM 43889=JCM 6095). The G+C content of the genome is 72.5 % and genome size is 5.97 Mbp.