Caridi Andrea, Cufari J Antonio, Ramondino Donatella
Department of Agro-Forestry and Environmental Technology and Science, Mediterranean University of Reggio Calabria, Piazza San Francesco 7, I-89061 Gallina (RC), Italy.
J Gen Appl Microbiol. 2002 Oct;48(5):261-7. doi: 10.2323/jgam.48.261.
The aim of the present study was to perform a fast pre-selection from a great number of wine yeasts using a simple phenotypic-based methodology that allows many different strains to be simultaneously tested. A total of 150 elliptic yeasts, isolated from must and wine from black grapes of a distinctive Italian variety, were studied. Yeasts were identified to genus level by assessing their ability to ferment glucose and their production of spores on acetate agar. The Saccharomyces strains were seeded on BiGGY agar to determine their H(2)S production, on calcium carbonate agar to test their acetic acid production, and on grape-skin agar and on grape-seed agar to assess their interaction with phenolic compounds. The Saccharomyces strains were also examined for fermentative vigor after 2 d or 7 d both with and without the addition of 100 mg L(-1) of SO(2) in must at 20 degrees brix and pH 3.20. At the end of fermentation, the wines produced by the 18 best yeasts were analyzed and the strains were studied for additional biochemical and technological characteristics. The resistance of the strains to simultaneous acid-stress and osmotic-stress was studied carrying out in duplicate winemaking tests in must at 30 degrees brix and pH 2.60. A remarkable heterogeneity among the 150 autochthonous yeasts studied was demonstrated. The phenotypical biodiversity is particularly interesting for several technological characteristics useful in winemaking, such as fermentation vigor, acetic acid production and malic acid content of the wines. The vast majority of the elliptic wine yeasts isolated did not show suitable characteristics, so only 18 strains, 12% of the total, remained for the final tests. Many of the strains that had passed the preliminary screenings revealed some defects when they were studied for fermentation performance, both in standard winemaking and under stressors. Two strains exhibited particularly interesting performances: one strain for winemaking of normal musts and the other for winemaking of musts from dried grapes or under stressful conditions.
本研究的目的是使用一种基于简单表型的方法，从大量葡萄酒酵母中进行快速预选，该方法允许同时测试许多不同的菌株。共研究了150株从一种独特的意大利黑葡萄品种的葡萄汁和葡萄酒中分离出的椭圆酵母。通过评估酵母发酵葡萄糖的能力及其在醋酸盐琼脂上产生孢子的能力，将酵母鉴定到属水平。将酿酒酵母菌株接种在BiGGY琼脂上以确定其H₂S的产生，接种在碳酸钙琼脂上以测试其醋酸的产生，并接种在葡萄皮琼脂和葡萄籽琼脂上以评估其与酚类化合物的相互作用。在20°Brix和pH 3.20的葡萄汁中，添加和不添加100 mg L⁻¹的SO₂的情况下，分别在2天或7天后检查酿酒酵母菌株的发酵活力。发酵结束后，分析了18株最佳酵母所酿造的葡萄酒，并研究了这些菌株的其他生化和技术特性。在30°Brix和pH 2.60的葡萄汁中进行重复的酿酒试验，研究了菌株对同时存在的酸胁迫和渗透胁迫的抗性。在所研究的150株本土酵母中表现出了显著的异质性。表型生物多样性对于酿酒中一些有用的技术特性特别有趣，例如发酵活力、醋酸产量和葡萄酒中的苹果酸含量。分离出的绝大多数椭圆葡萄酒酵母没有显示出合适的特性，因此最终测试仅剩下18株，占总数的12%。许多通过初步筛选的菌株在研究其在标准酿酒和应激条件下的发酵性能时显示出一些缺陷。有两株菌株表现出特别有趣的性能：一株用于正常葡萄汁的酿酒，另一株用于干葡萄或应激条件下葡萄汁的酿酒。
