Chlorophyll Fluorescence Parameters of Chlorella sorokiniana Exposed to Toxicants in the Presence of Activated Sludge and Fungus: Approaches to Wastewater Treatment

The resistance of green microalga Chlorella sorokiniana to the effect of certain toxicants (sodium dodecyl sulfate, formaldehyde, metribuzin) in the presence of activated sludge and the fungus Penicillium ochrochloron Biourge was studied using chlorophyll fluorescence methods. Detoxification of these substances increased under combined application of microalgae and activated sludge. Addition of activated sludge increased the photosynthetic activity of microalgae in the presence of sodium dodecyl sulfate (50 mg/L) and the herbicide metribuzin (0.01 and 0.05 mg/L). This was manifested in high values of the maximum quantum yield of photosystem II (F_V/F_M). Addition of the fungus P. ochrochloron revealed a decreasing toxic effect of the herbicide metribuzin at concentrations of 0.01 and 0.05 mg/L on the microalgae activity. Thus, the addition of activated sludge and the fungus P. ochrochloron to C. sorokiniana culture can be recommended in wastewater treatment technologies using microalgae, and chlorophyll fluorescence parameters (F_V/F_M) can be effectively used as indicators of the physiological state of microalgae in bioreactors under industrial conditions.