The effect of fluoranthene on the anaerobic fermentation of waste activated sludge: focusing on the mechanism of increased volatile fatty acid production and the reduction of antibiotic resistance genes

Published: 17 April 2023| Version 1 | DOI: 10.17632/nt6mwnvmj8.1
Contributor:
Qingyang Jiang

Description

Experimental data on the impact of fluoranthene on the production of volatile fatty acids by anaerobic fermentation of sludge and the removal of antibiotic resistance genes. The data includes the changes in the content of volatile fatty acids affected by fluoranthene. From the perspective of mechanism explanation, it includes the effects of fluoranthene on four stages of sludge fermentation :dissolution, hydrolysis, acidification, and acetogenesis. The impact of fluoranthene on the microbial community in the anaerobic fermentation system of sludge, key enzyme activity, abundance of key enzymes (proteases, carbohydrate enzymes), and the abundance of key genes in various metabolic pathways are also included. In addition, the data also includes the removal of antibiotic resistance genes in the system by fluoranthene.

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To investigate the accumulation of VFAs and the reduction of ARGs during the anaerobic fermentation of WAS under Flr stress, the experiment was conducted in 600mL glass bottles. The bottles were filled with 240mL WAS and concentration gradients of fluoranthene (0, 10, 50, 100, 200 and 500 mg fluoranthene/kg TSS). All fermentation reactors need to be adjusted PH to stabilize at 10.0 and to be blown with nitrogen (purity: 99.99%) for 5 min to maintain an anaerobic environment before sealing and placed in a constant temperature shaker for subsequent reactions. The whole WAS fermentation process was carried out at 37℃ and 160 rpm under shaker condition. Bovine serum protein (BSA, Mw67,000) and dextran (MW, 23,800) were used to simulate the hydrolysis process of protein and carbohydrate in order to study the effect of fluoranthene. The reactor contained 3000 mg / L BSA, 625 mg / L glucan, 24 mL domesticated sludge and 216 mL water. Under long-term operation conditions, the contents of BSA and glucan in the reactor were detected every day, and the degradation rate was calculated by the formula: Hydrolysis efficiency (%) = (C0 − C)/C0 × 100%, where C0 and C represent the initial and the measured degradation. The operation conditions of acidogenesis experiment were the same as those of hydrolysis experiment, except that 0.72 g L-glutamic acid and 0.15 g glucose were added into the reactor as the characterization substances of acid production metabolism instead of BSA and dextran. Similarly, the effect of fluoranthene on anaerobic fermentation acidogenesis of sludge was studied by measuring its degradation rate. The study of acetogenesis mainly depended on the addition of hydrogen and carbon dioxide, and the related effects were characterized by measuring the reduction rate of hydrogen partial pressure. The reactor contained 216 mL tap water, 24 mL domesticated sludge, 70% nitrogen, 20% hydrogen and 10% carbon dioxide (v / v). The hydrogen content in the reactor was measured once every two days and calculated with the same degradation rate formula. Metagenome method was used to analyze the relationship between microbial community structure, metabolic pathways, abundance of ARGs and CAZys. DIAMOND (https://github.com/bbuchfink/diamond) was used to compare non-redundant genes with NR, KEGG and CARD database (parameters: blastp; E-value ≤ 1e-5), and the annotation results were obtained from the corresponding database, The abundance of annotated substances was calculated using the sum of abundance. Hmmscan was used to compare the non-redundant gene set with the CAZy database, and the parameter settings were the same as above. The abundance of CAZys was calculated using the sum of the corresponding gene abundances. Analysis of variance was used to evaluate the significance of the results (P < 0.05).

Institutions

Tongji University

Categories

Metagenomics, Volatile Fatty Acid, Carbohydrate Metabolism, Proteases, Anaerobic Fermentation, Antibiotic Resistance

Funding

Tongji University

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