Using flow cytometry to monitor the stress response of yeast and microalgae populations in mixed cultures developed in brewery effluents

Recently, yeast and microalgae mixed cultures have been widely used in biological effluent treatments and biofuel production because such cultures show many advantages over pure cultures. However, industrial effluents often contain toxic compounds; therefore, it is important to evaluate the cell stress response when growing in such conditions during the mixed culture development. In this work, flow cytometry (FC) was used to differentiate Rhodosporidium toruloides cells from Tetradesmus obliquus cells, based on their size, internal complexity, and chlorophyll content. FC coupled with SYTOX Green and CFDA fluorochromes was also used to characterize the cell stress response of R. toruloides and T. obliquus individual cells in a mixed culture. This work describes, for the first time, a simple and easy method to monitor individual stress response of R. toruloides and T. obliquus cells growing in mixed cultures on brewery effluents, using FC coupled with fluorescent dyes.