Taxonomic revision of the cellulose-degrading fungus Acremonium cellulolyticus nomen nudum to Talaromyces based on phylogenetic analysis

The cellulase-producing fungal strain Y-94, isolated in Japan and invalidly described as Acremonium cellulolyticus nom. nud. strain Y-94, seldom forms enteroarthric conidia under nutrient starvation conditions. Phylogenetic analysis using ITS1-5.8S-ITS2 and RNA polymerase II large subunit gene sequences revealed that strain Y-94 is closely related to Talaromyces, given that these Y-94 sequences showed 100% identity with those of Talaromyces pinophilus NBRC 100533(T). By contrast, the identity between -tubulin-encoding genes from strain Y-94 and T.pinophilus NBRC 100533(T) was 98.1%. Morphological and phenotypic differences between these strains in colony color, conidiophore formation, and cellulase productivity were observed. Together, these data indicated that strain Y-94 belonged to the genus Talaromyces. We propose that strain Y-94 is a new species, Talaromyces cellulolyticus, on the basis of morphology and molecular evidence. The ex-holotype is Y-94 (=FERM BP-5826, CBS 136886 [holotype] TNS-F-48752).