Use of Prokaryotic and Eukaryotic Biotests to Assess Toxicity of Wastewater from 
Pharmaceutical Sources 

Jasna Hrenovic,^a* Bozidar Stilinovic,^a and Lujo Dvoracek^b 
a University of Zagreb, Faculty of Science, Department of Biology, Rooseveltov trg 6, HR-10000 Zagreb, Croatia
^b PLIVA - Research Institute plc, Prilaz baruna Filipovica 29, HR-10000 Zagreb, Croatia

 Abstract
The yeast toxicity test (YTT), based on the inhibition of saccharose fermentation by the yeast Saccharomyces cerevisiae, was evaluated using standard toxicants (copper sulphate, formaldehyde, sodium nitrite, sodium sulphite, phenol and zinc sulphate). Repeated measurements of YTT accuracy with the standard toxicants showed EC₅₀ values characterized by low standard deviation and coefficient of variation (7.62%). Moreover, the YTT was compared to standard prokaryotic biotests by estimating the toxicity of wastewater from pharmaceutical sources. The toxicity of wastewaters measured by YTT agrees sufficiently with those measured by standard methods of the determination of toxicity such as inhibition of bioluminescence, TTC-dehydrogenase activity, aerobic bacterial growth and anaerobic sludge biogas production. The YTT is a rapid, simple, reliable, sensitive and cost-effective method for presumptive estimations of the toxicity of wastewaters, which could be performed in laboratory as well as in field conditions.

Key words: biotest, pharmaceutical wastewater, Saccharomyces cerevisiae, yeast, toxicity test.