Inhibition on biological acidification and microbial community by high-strength acetaldehyde

Research on the biological removal of high-strength acetaldehyde solution is severely lacking; conse-quently, this study comprehensively investigated the impact of acetaldehyde on biological acidification. Our results indicate that the yield of acid production significantly decreased with increasing acetaldehyde concentration; the yield declined 14.83%-71.12% under the selected initial acetaldehyde concentrations of 100 to 2000 mg/L. Moreover, the acid-producing inhibition rate (EC50) was 1,118.36 mg/L according to calculations and non-linear fitting. Furthermore, DNA content under 1000 mg/L at 96 h was 2.22 times higher than that without acetaldehyde, which indicated that the inhibition of biological acidification by acetaldehyde was caused by microbial consortium death. In particular, microbes secreted more extra cellular polymeric substances to resist toxicity with 500 mg/L acetaldehyde, and protein-like substances in extracellular polymeric substances interacted with acetaldehyde. Finally, microbial consortiums were changed into a high-tolerance community of Chloroflexi,Actinobacteria, and Firmicutes at the phylum level after 96 h. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.