| Abstract |
During a survey of yeast strains having high conversion efficiency to ethanol from cellobiose, 'Ogataea pini' ATCC 28781 and 'Pichia pini' NBRC 1794 were found to be distinct from any known species and from each other by a BLAST homology search using the D1/D2 LSU rRNA gene sequences. The D1/D2 phylogeny showed that 'O. pini' ATCC 28781 and 'P. pini' NBRC 1794 belonged to the Ogataea cluster, whereas a comparison of the ITS 1 and 2 regions sequences showed that the ATCC and NBRC strains each formed a species distinct from O. ganodermae, O. pini, O. henricii, and P. zsoltii, based on the D1/D2 sequence divergence. The ATCC and NBRC strains formed two to four hat-shaped ascospores and two to four, or more ones per deliquescent ascus, respectively, were negative for DBB and urease reactions, assimilated methanol slowly and nitrate not at all, and had the major ubiquinone system Q-7. These characteristics coincided basically with the definition of Ogataea proposed by Yamada et al. in 1994, excluding the number of ascospores. On the other hand, the ATCC and NBRC strains differed not only from each other but from relatives in various phenotypic characteristics. These differences suggest that two new yeasts of Ogataea be described as novel. The new species and their type strains are as follows: O. neopini ATCC 28781(T); and O. corticis NBRC 1794(T). In addition, the emendation of the genus Ogataea is made; besides, we propose the transfer of P. zsoltii, P. dorogensis, and P. trehaloabstinens, which were placed in the Ogataea cluster based on the D1/D2 sequence analysis, to the genus Ogataea as O. zsoltii comb. nov., O. dorogensis comb. nov., and O. trehaloabstinens comb. nov.
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