Microorganisms with capacity for phosphate solubilization in Dão red wine (Portugal)

Luis Silva¹ , Raúl Rivas², Pedro F. Mateos², Eustoquio Martínez², Encarna Velázquez²

¹Agrarian College of Viseu, PORTUGAL.

²University of Salamanca, SPAIN

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The Dão is one designation by Portuguese wine of DO region (DOC). This region is mountainous, has a temperate climate and is localized in north central region of Portugal.

The mountains represent a rail important to defender the wines of the continental influences and maritime, the soil is levelled by Dão and Mondego River.

The minimum alcoholic level is 11%, this is full-bodied red wine which tone brownish with age and presented a fruit aroma. The malo-lactic fermentation of these wines is carried out in natural conditions for spontaneous fermentation. The principal alterations of wines are the production of acetic acid and those of volatile phenols.

In this work, we have been analysed ten samples of bottle red wine, after one minimum stage during 18 months in wood barrels to isolate strains potentially implied in alterations of red wines.

They were used ten different samples of red wine by Dão Region. This samples were inoculated in different plates of PCA (plate count agar) and TJA (tomato juice agar) medium, after yours growth, we have isolated the different microorganisms in this two mediums.

From this samples 68 bacterial strains were isolated and 12 of them showed solubilization of phosphate in YED-P plates. One of them has showed an unusually high capacity for phosphate solubilization (designated by 39PCAac1). These strain was identified by 16S rDNA sequencing as Gluconobacter oxydans subsp. oxydans, a strictly aerobic Gram negative rod. This species is one of the responsible for formation the acetic acid in wines and its ability to solubilize phosphates is few known.