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The degradative action of two strains of Saccharomyces cerevisiae, producers of large quantities of H2S and SO2, on eight sulphur-containing insecticides (chlorpyrifos-methyl, dimethoate, fenitrothion, fenthion, malation, methidation, parathion, and quinalphos) was studied. Moreover, the influence of these compounds on the fermentative activity of the yeasts was investigated. The yeasts adsorbed and degraded the studied insecticides to various extents, but their fermentative activity was not affected. A moderate adsorbtion (approximately 10% of the residue) was observed for chlorpyrifos-methyl, fenitrothion, parathion, and quinalphos. When absorbed, the insecticides were also degraded by about 50%. The degraded pesticides belong to the thiophosphates, while the dithiophosphates showed higher stability. The two yeast strains showed analogous degradative actions.

The action of a yeast (Saccharomyces cerevisiae) upon the insecticides Carbaryl, Tetrachlorvinphos and Deltamethrin and the fungicides Quinomethionate, Triadimefon and Vinclozolin during aerobic fermentation was investigated. The yeast adsorbed all the pesticides, four of them completely and two (Carbaryl, 50%, and Triadimefon, 90%) partially. In the case of Deltamethrin and Quinomethionate, degradation also occurred.

Fermentation tests in clearly defined laboratory conditions were carried out with eight functionally selected strains of Saccharomyces cerevisiae. Analysis of the data showed that there were no significant differences in malic acid production between the strains when the acid was initially present. When it was initially absent, however, significant differences were observed two strains (Nos. 1141 and 1083) showing marked productive superiority. With malic acid as the sole C source, two strains (Nos. 1109 and 1141) showed less acid consumption.

Continuing the investigation into possible yeast influence on ferment degradation of residual pesticides, two dicarboxymide antibotrytic fungicides (Iprodione and Procymidone), three acylanilide antiperonosporic fungicides (Benalaxyl, Furalaxyl and Ofurace) and two pyrethroid insecticides (Permethrin and Fenvalerate) were tested.