Pichia myanmarensis sp. nov., a novel cation-tolerant yeast isolated from palm sugar in Myanmar.

Four halotolerant yeast strains, M21(T), M34-1, HS054 and D41, were isolated from various foods in South-East Asia. These isolates were most closely related to Pichia anomala, with which each strain had from zero to two differences in the 26S rDNA D1/D2 domain nucleotide sequence; for this reason, they were thought to be the same as, or sister species of, P. anomala. Of the four yeast isolates, only one strain, M21(T), had an 18S rDNA sequence that differed from those of P. anomala IFO 10213(T) and the other three isolates, having 20 substitutions and two gaps. Strain M21(T) showed lower cation (Li(+)) tolerance (< or =0.3 M LiCl) than P. anomala IFO 10213(T) or the other three strains (< or = 0.5 M LiCl). Furthermore, the DNA-DNA hybridization data indicated that M21(T) was clearly distinct from P. anomala IFO 10213(T) and the other three isolates. The ability of strain M21(T) to assimilate d-arabinose distinguished it from P. anomala IFO 10213(T) and the other three isolates; it also differed in that it was able to grow at 37 and 40 degrees C. Strain M21(T) grew by multilateral budding, produced persistent asci, in which between one and four hat-shaped ascospores were formed, and contained ubiquinone Q-7. On the basis of this polyphasic characterization, strain M21(T) represents a novel species within the Q-7-containing group of the genus Pichia, for which the name Pichia myanmarensis is proposed. The type strain is M21(T) (= NBRC 11090(T) = JCM 12922(T) = CBS 9786(T)).