[The enzymatic hydrolysis of cell wall applied to yeasts classification (author's transl)]

The rigid structure of yeast cell wall may be a taxonomic criterion. Using the Helix pomatia juice (with mercaptoethylamine hydrochloride) as a polyenzymatic system, we have always obtained protoplasts from ascomycetous yeasts and never from basidiomycetous yeasts tested. Then, we have applied this enzymatic analysis to the Fungi imperfecti yeasts and, according to this test, separated genus looking like basidiomycetous behaviour: Trichosporon, Pityrosporum, Rhodotorula, Cryptococcus and non fermentative Candida (group II). Oppositely, we have put together the Fungi imperfecti yeasts looking like ascomycetous behaviour: Kloeckera, Trigonopsis, Brettanomyces and fermentative Candida (group I). With the second lytic system made of mercaptoethylamine-HCl and beta-(1-3)-D-glucanase, we have selected ascomycetous yeasts giving protoplasts: Saccharomycoidea with genus Saccharomyces, Kluyveromyces, Pichia, Hansenula, Citeromyces, Debaryomyces; we have joined Saccharomycodes and Hanseniaspora to this second group. The other ascomycetous yeasts studied did not give protoplasts with the definite lytic system made of purified beta-(1-3)-D-glucanase and thiol. These results seem to demonstrate that the structure of cell wall can act as an important taxonomic criterion.