Temperature-regulated and starvation-induced refractory para-toluic acid anaerobic biotransformation. (January 2023)

• Record Type: Journal Article
• Authors: Ma, Xiao-chen; Wang, Ke; Gao, Xin-lei; Li, Xiang-kun; Liu, Gai-ge; Chen, Hong-ying; Piao, Chen-yu; You, Shi-jie
• Is Part Of: Chemosphere. Volume 311:Part 2(2023)
• Publication Date: 2023-01
• Subjects: Para-toluic acid -- Thermophilic digestion -- Terephthalic acid -- Phthalic acid -- Starvation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.137008
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Little research was focused on the anerobic degradation of refractory para-toluic acid at present. Thus, temperature-regulated anaerobic system of para-toluic acid fed as sole substrate was built and investigated via microbiota, metabolism intermediates, and function prediction in this study. Results showed that low methane yield was produced in para-toluic acid anaerobic system at alkaline condition. And the causes were owing to anaerobic methane oxidation and potentially H2 S production at 37 °C, N2 production by denitrification before starvation and propionic acid occurrence after starvation at 27 °C, and production of N2 and free ammonia, and accumulation of acetic acid at 52 °C. Simultaneously, hydrogenotrophic methanogenesis dependent on syntrophic acetate oxidation (SAO) was predominant, facilitating the removal of para-toluic acid at 52 °C. Moreover, the key intermediate changed from phthalic acid of 37 °C and 27 °C before starvation to terephthalic acid of 52 °C. Starvation promoted removal of para-toluic acid through benzoyl-CoA pathway by Syntrophorhabdus, enrichment of syntrophic propionate degraders of Bacteroidetes and Ignavibacteriaceae, and increase of methylotrophic methanogens. Graphical abstract: Image 1 Highlights: Temperature variation and starvation changed para-toluic acid metabolic pathway. Temperature variation and starvation also changed dominant methanogens type. The key intermediate was phthalic acid at 37 °C and terephthalic acid at 52 °C. Benzoate and fatty acid metabolism were facilitated at 27 °C.