CONTRIBUCION AL CONOCIMIENTO DE LAS LEVADURAS DEL AGUAMIEL Y DEL PULQUE

Resumen

In this paper a new species of anascosporogenous yeast is described. We put it within the genus Rhodotorula and because of its specific characters we consider it as new under the name incarnata because of the red color it shows in all cultures. This yeast was isolated from the "aguamiel" produced by the "maguey" (Agave) and also from the "pulque" obtained from the fermented aguamiel.
The fundamental characters of this new species of yeast are:

1.- Culture in beer-wort: At 25° C. after 4 days a small sediment appears; after 15 days a ring is formed and after 20 days a mucous veil formed by the reunion of previously isolated areas. Ring, sediment and veil are flesh-colored. At the same temperature, after 3 days oval cells are obtained, isolated, with granular protoplasm, the majority with a single bud, sorne with several in crown form (3.5-4 by 4-6 micra).
2.-Culture in wort-agar: At 25° C. after 12 days circular colonies are obtained, with smooth surface, convex elevation, entire borders, pink-redish in color, shiny and with a mucous consistency. After 48 hours, cells are oval-elongated, clearly oval after 10 or 15 days. (3-3.5 by 6-7 micra).
It is interesting to mention that after 30 dyas in these media, some cells appear producing protoplasmic elongations as if they were to enter in conqugation, which is never observad in other cases. Cells of this type are extremely numerous in media with "aguamiel".
3.-Streak-culture. In wort-agar after 15 days at 25° C. they show en equinulated form, finely striated surface, convex elevation, undulated borders, incarnate in color, intensely shiny and a viscous consistency.
4.-Giant colonies. In wort-gelatin no giant colonies can be obtained because of the early liquefaction of the medium. In wort-agar they acquire characters similar to those mentioned above.
5.- Asci and ascospores. Even following the most diverse techniques specially recomended no asci or ascospores were formed.
6.- Liquefaction of gelatin. Results clearly positive; after 10 days, this process begins and is finished after 20 or 30 days.
7.-Fermentation. Does not ferment any sugars.
8.- Selectivity to sugars:
Dextrose +                   Saccharose +
Levoluse +                    Maltose +
Manase +                      Lactose + (very little)
Galactosa + (a little)    Raffinose ?
9.-Assimilation of Nitrogen:
Potassium nitrate +       Peptone +
Amonium sulphate +     Asparagine +
                             Urea +
10.- Ethyl alcohol as substratum for development: Very little, even after 30 days.