Production of volatile phenols by Pichia manshurica and Pichia membranifaciens isolated from spoiled wines and cellar environment in Patagonia

In order to detect spoilage yeast species in wines showing off-odors, different yeast isolation protocols were evaluated. Independently of the isolation method, only Saccharomyces cerevisiae and Pichia manshurica were detected. The spoilage capacity of P. manshurica regional isolates was evaluated in red wine and the production of volatile phenols was evidenced. To evaluate the possible source of contamination, yeasts from both grapes and cellar surfaces were obtained. Hanseniaspora uvarum and Zygoascus hellenicus were detected in both sound and damaged grapes from sunny areas. The most frequent species in cellar surfaces was Candida boidinii, Pichia membranifaciens and P. manshurica were detected in filters. The intra-specific genetic characterization of the P. manshurica isolates by mtDNA-RFLP demonstrated that the same strain was detected in both wine and filter. Most P. membranifaciens isolates produced 4-EP (maximum level of 1.895 mg/L) and particularly high levels of 4-EG (maximum level of 10.260 mg/L) were produced by P. manshurica isolates in synthetic wine-like medium. In this work the capacity of P. manshurica and P. membranifaciens species to produce volatile phenols was shown for the first time.

Research highlights
► In this work the capacity of Pichia manshurica and Pichia membranifaciens species to produce volatile phenols was shown for the first time.