Zygosaccharomyces sapae sp. nov., a novel yeast species isolated from Italian traditional balsamic vinegar.

Fourteen yeast isolates were recovered from two traditional balsamic vinegar (TBV) samples collected in the provinces of Modena and Reggio Emilia, Italy. Microsatellite-primed-PCR (MSP-PCR) was used to de-replicate the isolate collection into two representative strains, ABT301T and ABT601. Phylogenetic analysis based on the D1/D2 domains of the 26S rRNA gene indicated that these strains represented a distinct species of the Zygosaccharomyces genus, closely related to Zygosaccharomyces rouxii and Zygosaccharomyces mellis. Physiological and morphological tests supported the recognition of a novel taxon of halotolerant, osmotolerant, non-psychrotrophic, and maltose-fermenting negative yeasts showing a chain or star-shaped pattern of budding cells, which remain attached to each other. Morphological observation offered evidence of ascospore formation. In this work, we propose a novel species, Zygosaccharomyces sapae sp. nov., to accommodate these strains, with strain ABT301T (= CBS 12607T = MUCL 54092T) designated as the type strain. The MycoBank number of the new species is MB 564957. Based on D1/D2 domain phylogenetic analysis, the novel strains shared the highest sequence similarity (100%) with Zygosaccharomyces sp. strain NCYC 3042, previously isolated from sugar [James et al. (2005) FEMS Yeast Res 5, 747-755]. However, based on phylogenetic (internal transcribed spacers, ITS), PCR fingerprinting and physiological analyses, marked differences were observed between the the novel species and strain NCYC 3042, and these results are discussed in more detail.