Macrowine 2021
IVES 9 IVES Conference Series 9 Screening of soil yeasts with fermentative capacity from the antarctic continent for their application in the wine industry

Screening of soil yeasts with fermentative capacity from the antarctic continent for their application in the wine industry

Abstract

AIM: In the last years, many wineries are increasing experimentation to produce more distinguishable beverages. In this sense, the reduction of the fermentation temperature could be a useful tool because it preserves volatile compounds and prevents wines from browning, particularly in the case of white wines. However, low fermentation temperatures usually produce an early stop in the fermentation. Hence, the employment of new yeast strains able to operate at low temperatures could solve this problem, giving rise to different characteristics in wines. The Antarctic Continent is a crucial source for the isolation of new microorganisms and bioactive metabolites, given the competitive conditions of this environment with low temperatures, scarce carbon sources and high UV radiation. Considering this, the objective of this study was the isolation and characterization of fermentative yeast from the Antarctic Continent with potential for use in the wine industry.

METHODOLOGY: Six soil samples collected in Fildes Bay, west of King George Island and three soil samples from King George Island were processed for yeast isolation. Samples were suspended in sterile water and dilutions of each suspension were inoculated onto yeast medium (YM) agar plates with antibiotics, which were then incubated at 4, 10, and 18 °C until visible colony growth. Colonies with a non-filamentous appearance were selected, which were reseeded on YM agar without antibiotics. Alcohol tolerance was performed using concentrations of 3, 6, or 9% alcohol. Later on, sugar tolerance was analyzed using fructose and glucose in a 1:1 proportion; with 5, 10, 15, 20, or 25% of sugar in the medium. Those isolates with microscopic characteristics of interest were selected to determine fermentative activity in vitro using a simple colorimetric assay with phenol red, as a pH indicator. To differentiate the isolates, and discard replicates, a fingerprinting assay with arbitrary primers was performed. Identification of the isolates was carried out using PCR and ITS region primers with BLAST bioinformatics tools.

RESULTS: Nine soil samples collected from the Antarctica were processed for yeast isolation. We obtained 125 yeasts from the soil samples, with a growth temperature of 10ºC. Overall, 25 yeasts have fermentative activity and are able to tolerate a culture medium with at least 20% glucose and up to 6% of ethanol. The isolates were also characterized by optical microscopy and fingerprinting using PCR with arbitrary primers to discard identical strains and allowed us to discriminate 10 unique strains with fermentative capacity from the 25 isolates. To determine the identity of the isolated yeasts, the amplification and sequence of the 18S RNA was performed.

CONCLUSION:

The Antarctic continent has proven to be a source of fermentative yeasts with high potential for their use in the wine industry.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Laura Navarro, Cristina Úbeda, Mariona Gil i Cortiella, Ana Gutierrez, Gino Corsini, Nancy Calisto

Biomedical Sciences Institute, Health Sciences Faculty, Autonomous University of Chile, Santiago, Chile., Nutrition and Food Sciences Department, Faculty of Pharmacy, University of Seville, Seville, Spain. Applied Chemical Sciences Institute, Autonomous University of Chile, Santiago, Chile. Biomedical Sciences Institute, Health Sciences Faculty, Autonomous University of Chile, Santiago, Chile. Biomedical Sciences Institute, Health Sciences Faculty, Autonomous University of Chile, Santiago, Chile. Chemical engineering department, Faculty of Engineering, Magallanes University, Punta Arenas, Chile. Biomedical Sciences Institute, Health Sciences Faculty, Autonomous University of Chile, Santiago, Chile.

Contact the author

Keywords

antarctic yeast, low temperature fermentation, yeast isolation, yeast characterization

Citation

Related articles…

The modification of cultural practices in grapevine cv. Syrah, does it modify the characteristics of the musts?

The work shows the results of a year of experimentation (2020) in a Syrah variety vineyard in La Roda (Castilla-La Mancha, Spain). The trial approach was on a randomized block design with two factors: Irrigation (I) and Pruning (P).
Irrigation schedules were adjusted to apply amounts close to 1,500 m3/ha. With this provision, 2 different irrigation treatments were proposed: I1) Start of irrigation from pea-sized grape to post-harvest (providing at least 20 % of the total amount of irrigation water to be provided post-harvest); I2) Start of irrigation from pea-sized grape to harvest (usual irrigation practice in the study area). Pruning was proposed with two treatments, one at the end of January (P1), which is pruning on a conventional date; and P2) pruning carried out at the beginning of budding. In total, 4 repetitions were designed with 4 elementary plots, each one of them representing one of the proposed treatments (I1P1; I1P2; I2P1; I2P2). In total, 16 plots were worked on and each elementary plot consisted of 30 strains, distributed in 3 lines.
The productive response was evaluated with the yield results of the harvest harvested at 23 ºBrix. The qualitative response was measured in the musts through the indices of technological (acidity, pH and potassium) and phenolic maturity and aromatic compounds in free and glycosylated fractions. The treatments tested had, in general, an effect on the different variables analyzed.

Differential responses of red and white grape cultivars trained to a single trellis system – the VSP

Commercial grape production relies on training grapevine cultivars onto a variety of trellis systems. Training allows for well-lit leaves and clusters, maximizing fruit quality in addition to facilitating cultivation, harvesting, and diseases control. Although grapevines can be trained onto an infinite variety of trellis systems, most red and white cultivars are trained to the standard VSP (Vertical Shoot Positioning) system. However, red and white cultivars respond differently to VSP in fruit composition and growth characteristics, which are yet to be fully understood. Therefore, the objective of this study was to examine the influence of the VSP trellis system on fruit composition of three red, Cabernet Sauvignon, Merlot and Syrah, and three white, Chardonnay, Riesling, and Gewurztraminer cultivars grown under uniform growing conditions in the same vineyard. All cultivars were monitored for maturity and harvested at their physiologically maximum possible sugar concentration to compare various fruit quality attributes such as Brix, pH, TA, malic and tartaric acids, glucose and fructose, potassium, YAN, and phenolic compounds including total anthocyanins, anthocyanin profile, and tannins. A distinct pattern in fruit composition was observed in each cultivar. In regards to growth characteristics, Syrah grew vigorously with the highest cluster weight. Although all cultivars developed pyriform seeds, the seed size and weight varied among all cultivars. Also varied were mesocarp cell viability, brush morphology, and cane structure. This knowledge of the canopy architectural characteristics assessed by the widely employed fruit compositional attributes and growth characteristics will aid the growers in better management of the vines in varied situations.

Better understand the soil wet bulb formation with subsurface or aerial drip irrigation in viticulture

The gradual change in rainfall patterns experienced in the south of France vineyards, especially around the Mediterranean sea, means that the vines are increasingly subject to summer drought. The winegrowers developped the use of irrigation techniques to ensure the maintenance of competitive yields in the production of wines under Protected Geographical Indication label. In practice, drip irrigation pipes can be installed above the ground or buried into the soil as well as at different distances from the vine row. The objective of this study was to examine the profiles of the wet bulbs of the soil obtained from two drip irrigation systems : aerial drip located under the vine row and subsurface drip placed in the middle of the inter-row. This experiment took place over two consecutive seasons (2020-2021) on a 3.4 ha Viognier plot in the Mediterranean region (PGI Oc, France) on sandy clay soil. The annual rainfalls were less than 400 mm. Soil water content probes were installed at different depths (20 – 40 – 60 – 80 cm) and at different lateralities from the vine row (30 – 60 – 90 – 120 cm) to control the formation of the soil wet bulb during irrigation. The mapping and the analysis of the data allowed a better understanding and differentiation of the water percolation when irrigating with subsurface or aerial drip. For the same amount of water and without differences of vine water status, it is shown that in a subsurface drip irrigation situation, the size of the wet bulb formed is larger than in aerial drip irrigation system.

Modeling island and coastal vineyards potential in the context of climate change

Climate change impacts regional and local climates, which in turn affects the world’s wine regions. In the short term, these modifications rises issues about maintaining quality and style of wine, and in a longer term about the suitability of grape varieties and the sustainability of traditional wine regions. Thus, adaptation to climate change represents a major challenge for viticulture. In this context, island and coastal vineyards could become coveted areas due to their specific climatic conditions. In regions subject to warming, the proximity of the sea can moderate extremes temperatures, which could be an advantage for wine. However, coastal and island areas are particular prized spaces and subject to multiple pressures that make the establishment or extension of viticulture complex.
In this perspective, it seems relevant to assess the potentialities of coastal and island areas for viticulture. This contribution will present a spatial optimization model that tends to characterize most suitable agroclimatic patterns in historical or emerging vineyards according to different scenarios. Thanks to an in-depth bibliography a global inventory of coastal and insular vineyards on a worldwide scale has been realized. Relevant criteria have been identified to describe the specificities of these vineyards. They are used as input data in the optimization process, which will optimize some objectives and spatial aspects. According to a predefined scenario, the objectives are set in three main categories associated with climatic characteristics, vineyards characteristics and management strategies. At the end of this optimization process, a series of maps presents the different spatial configurations that maximize the scenario objectives.

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.