Argentina ranks worldwide among the top ten wine producers, known for its diverse terroirs and Malbec as its emblematic varietal. Typically, the winemaking process involves alcoholic fermentation, led by yeasts, and malolactic fermentation (MLF), primarily driven by lactic acid bacteria (LAB). Oenococcus oeni and Lactiplantibacillus plantarum are recognised as the best-adapted LAB species for this process. Our previous research focused on a winery located in the southwest of Buenos Aires Province, a scarcely studied re-emerging region of Argentina, which showed a low relative abundance of LAB and incomplete MLF in various vintages. The current study involved the isolation, identification, typing, and use of native strains from the above-mentioned region to formulate a malolactic fermentation starter (MLFS) and to evaluate the strains’ malolactic performance at pilot-scale, implantation capacity and impact on wine aromatic profiles using HS-SPME-GC-FID/MS. Two selected autochthonous strains (Lpb. plantarum UNQLp1001 and a O. oeni UNQOe1101) from the re-emerging region successfully implanted in Malbec wine, achieving faster and more efficient MLF compared to spontaneous MLF. Moreover, the MLFS seems to have influenced the aromatic profile, reducing relative concentrations of alcohols, contributing to the decrease in the bitter and herbaceous notes, and increasing some esters (ethyl acetate, 2-phenethyl acetate, ethyl octanoate), that could enhance floral and fruity, notes. Expanding the availability of candidate strains to formulate native MLFS is a crucial technological tool for the wine industry. Thus, we propose the use of Lpb. plantarum UNQLp1001 and O. oeni UNQOe1101 as potential MLFS in Malbec wines from somewhat similar wine-producing regions. Additionally, the local winery can access a cost-effective MLFS with native LAB strains, enabling a more controlled MLF that preserves regional typicity. Moreover, these strains could enable technology transfer, potentially becoming the first malolactic starters in the region.

Argentina se ubica entre los países “top 10” del planeta en lo referido a industria vitivinícola, siendo el 7º productor mundial de vino, el 8º exportador, y el 9º consumidor. Las regiones vitivinícolas tradicionales han sido extensamente estudiadas mediante técnicas que dependen del cultivo de microorganismos en el laboratorio, y en menor medida por técnicas independientes del mismo. Sin embargo, regiones que han estado relegadas por razones políticas, económicas y sociales, hoy son reconocidas como re-emergentes a nivel productivo, pero se encuentran estudiadas muy pobremente o permanecen sin estudiar. La provincia de Buenos Aires se ubica como una región re-emergente de interés socio-económico y cultural debido a su crecimiento en vitivinicultura durante los últimos 20 años. El objetivo del presente trabajo consistió en estudiar por técnicas dependientes e independientes de cultivo, una muestra de mosto de la vendimia 2018 de una bodega bonaerense, con especial énfasis en la comparación de las bacterias del ácido láctico (BAL) detectadas mediante ambos tipos de estudios. Se lograron obtener 6 cepas de BAL: 4 cepas de Lactiplantibacillus plantarum, 1 cepa de Enterococcus mundtii y 1 cepa de Enterococcus durans. La caracterización inicial de las cepas de Lpb. plantarum mediante el estudio de sus cinéticas de crecimiento y resistencia al etanol, permitió sugerirlas como posibles candidatos para la futura formulación de iniciadores de fermentación maloláctica (FML). Por otra parte, mediante la secuenciación masiva del gen 16S rRNA, se observó que los filos más abundantes fueron Proteobacterias, Actinobacterias y Firmicutes, sin embargo, no se lograron encontrar miembros del orden Lactobacillales, al que pertenecen las BAL. Los resultados del presente trabajo refuerzan la necesidad de realizar análisis integrales que permitan incrementar la sensibilidad de detección de BAL en muestras de mosto y vino de estas regiones vitivinícolas re-emergentes. Estudios como el presente, podrían resultar relevantes para nuestro país, ya que pueden contribuir con los productores a identificar y resolver inconvenientes, y aportar con sugerencias para mejorar el proceso fermentativo a fin de obtener vinos de mayor calidad e incrementar su valor agregado.

Malolactic fermentation conducted by lactic acid bacteria is essential for enhancing wine’s sensory qualities. Although this process can occur spontaneously through the action of native lactic acid bacteria (LAB) from the grapes and cellar, it carries risks such as increased volatile acidity, consumption of residual sugars, and the formation of undesirable metabolites like biogenic amines. This study evaluated the oenological potential of three innovative native malolactic fermentation starters (MLFS) on a pilot scale, aiming to offer local wineries cost-effective MLFS with native LAB strains. Alcoholic fermentation of Malbec grapes was carried out using a commercial yeast starter, followed by a sequential inoculation of native malolactic starters formulated with (i) mesophilic Lactiplantibacillus plantarum UNQLp11 and Oenococcus oeni UNQOe73.2, both from the Province of Río Negro; (ii) psychrotrophic Lentilactibacillus hilgardii UNQLh1.1 and Oenococcus oeni UNQOe19, both from the Province of Río Negro; (iii) mesophilic Lactiplantibacillus plantarum UNQLp1001, from the Province of Buenos Aires; and (iv) a commercial malolactic started, which served as a control. Malic acid was consumed by all starters. RAPD-PCR using M13 primer showed the native LAB’s capability for implantation in wine. A sensory analysis revealed distinct profiles for each formulation, despite having been inoculated at the end of the same alcoholic fermentation. These MLFS could replace imports, enhancing the region’s unique terroir.