Malolactic fermentation (MLF) is a biological process of deacidification of wines that may also help to increase the microbiological stability of the product and to enhance its sensorial attributes, in particular its aromatic profile. MLF can occur spontaneously due to the presence of indigenous bacteria in the environment of fermented beverages such as wines and ciders. However, the inoculation of lactic acid bacteria (LAB) starter cultures could prevent potential losses and standardize the process. The industrial-scale production of these starter cultures requires cost-effective, sustainable, and feasible approaches. A possible approach to acquire bacterial biomass, while addressing waste disposal concerns, is the use of by-products from the apple juice industry, such as apple pomace. Moreover, to ensure the long-term viability and activity of starter cultures, appropriate preservation methodologies need to be developed. Thus, the aim of the present study was to evaluate the growth of two Lactiplantibacillus plantarum strains, UNQLp11 and UNQLp155, in supplemented apple pomace and to optimize the preservation conditions. Cultures were either frozen or freeze dried (trehalose (20% m/v) as a protective agent, potassium phosphate buffer (pH 7), and a combination of trehalose and buffer), and then cell viability and malolactic activity were analyzed under wine stress conditions. Notably, the combination of phosphate buffer at pH 7.0 and trehalose emerged as the most effective preservation strategy for freeze drying, exhibiting enhanced viability and malic acid consumption for the two strains evaluated. These findings underscore the inexpensive and sustainable viability of using a semi-solid medium formulated with apple pomace for LAB biomass production and subsequent preservation.

The Lacticaseibacillus paracasei UNQLpc 10 strain was isolated from a Malbec wine produced in North Patagonia, Argentina, and identified by 16S rRNA gene sequencing. The aim of this work was to obtain the fully assembled genome of the UNQLpc 10 strain, analyze its structure, and evaluate the possible functions of the predicted genes with regard to its oenological potential as a malolactic starter. UNQLpc10 is the first whole assembled genome of an oenological strain of Lcb. paracasei reported in databases. This information is of great interest inexpanding the knowledge of diversity of oenological lactic acid bacteria and in searching for new candidate species/strains to design starter cultures. The in silico genome-wide analysis of UNQLpc 10 confirms the existence of genes encoding enzymes involved in the synthesis of several metabolites of oenological interest, and proteins related to stress responses. Furthermore, when UNQLpc 10 was incubated in synthetic wine, it exhibited a very good survival and L-malic acid consumption ability.

Beer lees (BL), a by-product of beer production, consist mainly of dead yeast cells with potential nutritional value. On the other hand, yeast extract (YE), obtained through the lysis of yeast cells, is commonly used as a nutrient-rich supplement for the growth of fastidious microorganisms such as lactic acid bacteria (LAB). However, YE is a high-cost ingredient. Therefore, the aim of this study was to optimize the use of BL as a low-cost alternative source of YE through different lysis treatments, evaluating its suitability to support the growth of UNQLpc 10 and UNQLp 11 strains in a whey permeate (WP)-based medium. Growth kinetics and cell viability were compared with those obtained in MRS broth. The best results were observed with sonicated BL, up to 10 logarithmic units, which supported LAB growth comparable to MRS. Although autolyzed BL promoted lower bacterial growth than sonicated BL, it showed greater cell disruption and higher levels of nitrogen, proteins, and amino acids (5.32%, 26.0%, and 277 nM, respectively). Additionally, autolyzed BL exhibited lower concentrations of reducing sugars and a higher presence of Maillard reaction products, as indicated by colorimetric analysis. These changes, which may be related to the formation of Maillard reaction products during the autolysis process, could have negatively affected the nutritional quality of the extract and, thus, reduced its effectiveness as a bacterial growth promoter.

Durante la vinificación, la fermentación maloláctica (FML) es conducida por bacterias ácido lácticas (BAL), capaces de disminuir la acidez total y definir el perfil aromático del vino. En Argentina para controlar la FML se emplean cultivos iniciadores con cepas de otras regiones del mundo, por lo cual, la formulación de iniciadores malolácticos con cepas nativas seleccionadas por su potencial enológico resulta una estrategia de gran impacto sobre el sector vitivinícola y las economías regionales. Estos iniciadores deben poseer propiedades tecnológicas para sobrevivir a las estresantes condiciones del vino y ser presentados en formato deshidratado que facilita su preservación y futura comercialización. Para la formulación de cultivos iniciadores a gran escala resulta necesario optimizar la obtención de biomasa de BAL autóctonas. Para esto, el uso de subproductos de la industria alimenticia posibilitaría la sustitución de los medios de cultivo comerciales. Esta innovación contribuye a pensar la elaboración de iniciadores autóctonos de forma sustentable, aportar valor agregado sobre el carácter regional de los vinos y preservar la tipicidad del terruño. Este trabajo tuvo como objetivos, en primer lugar, optimizar el crecimiento de la cepa UNQOe19 de Oenococcus oeni en medios alternativos formulados con los subproductos de la industria alimenticia bagazo de manzana y permeado de suero leche. En segundo lugar, evaluar las propiedades tecnológicas de la cepa UNQOe19 de O. oeni mediante el estudio de la tolerancia a diferentes condiciones de pH, alcohol, sulfitos, lisozimas y preservación por liofilización. La cepa UNQOe19 mostró crecimiento en ambos sustratos alternativos suplementados con extracto de levadura y sales. Además, mostró tolerancia a la presencia de sulfitos (SO2), pH ácidos, etanol al 10% y conservó la viabilidad durante el proceso de liofilización para su futura presentación como iniciador maloláctico en formato sólido.

Wine lees (WL) are one of the main byproducts generated during winemaking and are usually disposed of in landfills or incorporated into the soil as an organic amendment; nevertheless, these practices can have negative environmental impacts. Reusing agro-industrial byproducts is a key step toward more sustainable production cycles, and WL represent a promising alternative for formulating culture media for the production of lactic acid bacteria (LAB) biomass, microorganisms widely used in the food and wine industries. In this work, we aim to evaluate the ecotoxicity of WL using a bioassay with zebrafish (Danio rerio) embryos and to analyze their potential as a source of nitrogen and growth factors for the production of UNQLp 11 Lactiplantibacillus plantarum strain biomass in whey permeate. Trials conducted with zebrafish showed that embryos exposed to WL exhibited increased mortality in a concentration-dependent response and the appearance of sublethal effects, such as alterations in embryonic development. Regarding WL biotechnological application, the results obtained confirm that the growth of Lpb. plantarum depends largely on the composition of the culture medium. Whey permeate media (WP) without supplementation showed nutritional limitations, reflected in lower cell counts. While supplementation with WL significantly improved bacterial growth, in some cases reaching values comparable to those obtained with MRS. The results demonstrated that WL can act as an efficient nutrient source, with the potential to replace commercial yeast extract in Lpb. plantarum culture media.

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.