VIEW ARTICLE    DOI: 10.1094/ASBCJ-35-0012

Use of Immunological Methods in the Interspecies Relationships of Genus Saccharomyces and its Possible Application in Detection of Contaminating Strains. C. Callejas, M. A. Rodríguez, and A. M. Canales, Cervecería Cuauhtémoc, S.A., Monterrey, N.L., México. J. Am. Soc. Brew. Chem. 35:0012, 1977.

Immunological methods have been used in order to detect contaminating yeast and metabolic variants during the brewing process. This paper describes some of our results using this methodology and comparing established brewing yeast strains with several contaminants isolated during the brewing process. Six yeast strains of the genus Saccharomyces were used, two of them well characterized: S. uvarum CC15i30 and S. cerevisiae var. ellipsoideus. The other four strains were isolated during the brewing process; two of them (3/24 and 5/24) produce diacetyl; the other two strains (A51 and A66) produce variable amounts of phenol. Agglutination technique was rather coarse for our purposes and we decided to rely mostly on the more powerful analytic immunodiffusion technique in gel, described by Ouchterlony. Two series of tests were run: in one, antigens were placed in the center well and the antisera in the surrounding wells, and in the other, the reverse was done. The first test differentiated S. uvarum from S. cerevisiae var. ellipsoideus, since S. uvarum has antigens which are not shared with S. cerevisiae var. ellipsoideus. Antigens of contaminants 3/24, 5/24, A51, and A66 show a considerable cross reactivity with their antisera, but seldom react with S. uvarum and S. cerevisiae var. ellipsoideus antisera. By means of the second test, with S. uvarum antiserum placed in the center well, S. uvarum was differentiated from S. cerevisiae var. ellipsoideus, but when antiserum from S. cerevisiae var. ellipsoideus was placed in the center well, it was not possible to differentiate them.

Keywords: Antigen-antibody reactions, Antigenic relations, Immunodiffusion, Immunological pattern, Yeast strains.