Cultivation of Chlorella vulgaris in sludge extract from resorcinol‐rich wastewater: the removal and inhibitory effect of sludge toxicity

Abstract

AbstractBACKGROUNDThe cultivation of Chlorella vulgaris present in toxic sludge extract from resorcinol‐rich wastewater was investigated to simultaneously determine the biomass production and toxicity removal.RESULTSA comparison of the blank and the toxic sludge extract revealed that the sludge toxicity originating from the degradation of resorcinol was highly correlated to the mass fraction at 5000–10000 Da (R = 0.987, P = 0.013) and led to a decline in biomass (1.49 g L−1 to 1.36 g L−1 in 30 days) along with a reduced utilization rate of organics in the sludge extract, especially in the early stage (0–5 days) of culture. The effects of sludge toxicity were characterized by the downregulation of proteins associated with carbon (C) metabolism and the upregulation of proteins involved in photoreaction by proteomics.CONCLUSIONThe sludge toxicity directly caused a decline in biomass production of C. vulgaris resulting from the downregulation of C metabolism. However, the promotion of biomass for heterotrophism was more significant than the inhibitory effect in the toxic sludge extract when compared with BG11 medium. © 2018 Society of Chemical Industry