Zygosaccharomyces sapae sp. nov., 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, ABT301(T) 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 genus Zygosaccharomyces, closely related to Zygosaccharomyces rouxii and Zygosaccharomyces mellis. Physiological and morphological tests supported the recognition of a novel taxon of halotolerant, osmotolerant, non-psychrotolerant and maltose-fermentation-negative yeasts showing a chain or star-shaped pattern of budding cells, which remained attached to each other. Morphological observations offered evidence of ascospore formation. A novel species, Zygosaccharomyces sapae sp. nov., is proposed to accommodate these strains, with strain ABT301(T) (= CBS 12607(T) = MUCL 54092(T)) as the type strain. 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, S. A., Bond, C. J., Stratford, M. & Roberts, I. N. (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 novel species and strain NCYC 3042, and these results are discussed in more detail.