Mbiriso, mumera kana mvuriro (yeast) idzinde risingaoneki nemeso risina ruvara rine cell imwe chete. Inowanikwa muchikwata cheAscomycetes murudzi rwemaFungi (anosanganisirawo chabvubvu). Mumbiriso munowanikwa maenzyme anoshanda, uye anoshandiswa mukubika doro nekuti chingwa chifute.