Effect of Nonylphenol on Anaerobic Fermentation of Waste Activated Sludge for Short-chain Fatty Acids Production Based on Metagenomic Analysis

Abstract:

The effect of environmental estrogen nonylphenol （NP） on the anaerobic fermentation of waste activated sludge for short-chain fatty acids （SCFAs） production was investigated， and the mechanism was revealed by means of metagenomic sequencing. It was found that NP promoted the SCFAs production during the anaerobic fermentation of the sludge， and the acceleration increased firstly and then decreased with the increase of NP concentration. The yield of SCFAs reached the maximum when the content of NP was 200 mg·kg^-1 dry sludge， which was 2-fold of that in the control. The production of acetic acid was increased by almost three times due to the presence of NP. Mechanism exploration based on metagenomic analysis exhibited that the reduction of acid-consuming and the improvements of acidogenic microorganisms was advantageous to the accumulation of SCFAs with NP. In addition， the relative abundance of functional genes in glycolysis， deamination and β-oxidation of glucose， amino acid and fatty acid was improved obviously. Also， the abundance of genes in adenosine triphosphate binding box transporters （ABC transporters） which control the transport of organic substrates into cells， two-component system for the SCFAs metabolism， and ABC transporters on SCFAs efflux increased remarkably. Furthermore， the abundance of genes related to biofilm formation regulated by quorum sensing in the presence of NP was increased， which was beneficial to cell growth and defense.