Potential production of 2-phenylethanol and 2-phenylethylacetate by non-Saccharomyces yeasts from Agave durangensis

Abstract

The participation of non-Saccharomyces yeasts in fermentation processes is of great importance due to their participation in the formation of esters and superior alcohols, which confer characteristic aromas to beverages such as wine and mescal. The aim of this study was identify and evaluate the potential aroma production of yeast native of Agave fermentation by the mescal production in Durango, Mexico. Isolated yeasts were molecularly identified by 5.8s ribosomal gene; the potential production of aromas was carried out in fermentations with the addition of l-phenylalanine and evaluated after 24 h of fermentation. Extraction and quantification of aromatic compounds by headspace solid-phase micro-extraction (HS-SPME) and gas chromatograph mass spectrometry (GC-MS). The isolated non-Saccharomyces yeasts could be classified into six different genera Saccharomyces cerevisiae, Clavispora lusitaniae, Torulaspora delbrueckii, Kluyveromyces dobzhanskii, Kluyveromyces marxianus, and Kluyveromyces sp. All probed strains presented a potential aroma production (ethyl acetate, isoamyl acetate, isoamyl alcohol, benzaldehyde, 2-phenylethyl butyrate, and phenylethyl propionate), particularly 2-phenylethanol and 2-phenylethylacetate; the levels found in the Kluyveromyces marxianus ITD0211 yeast have the highest 2-phenylethylacetate production at 203 mg/L and Kluyveromyces marxianus ITD0090 with a production of 2-phenylethanol at 1024 mg/L. Non-Saccharomyces yeasts were isolated from the mescal fermentation in Durango; the Kluyveromyces genus is the most predominant. For the production of aromas, highlighting two strains of Kluyveromyces marxianus produces competitive quantities of compounds of great biotechnological interest such as 2-phenylethanol and 2-phenylethylacetate, without resorting to the genetic modification of yeasts or the optimization of the culture medium.