Magnetic biochar promotes the risk of mobile genetic elements propagation in sludge anaerobic digestion

Yanru Zhang; Yinping Xiang; Rui Xu; Jing Huang; Jiaqin Deng; Xuan Zhang; Zijian Wu; Zhongliang Huang; Zhaohui Yang; Jingliang Xu; Wenlong Xiong; Hui Li

doi:10.1016/j.jenvman.2023.117492

Magnetic biochar promotes the risk of mobile genetic elements propagation in sludge anaerobic digestion

J Environ Manage. 2023 Jun 1:335:117492. doi: 10.1016/j.jenvman.2023.117492. Epub 2023 Feb 28.

Authors

Yanru Zhang¹, Yinping Xiang², Rui Xu³, Jing Huang⁴, Jiaqin Deng⁴, Xuan Zhang⁴, Zijian Wu⁴, Zhongliang Huang⁴, Zhaohui Yang², Jingliang Xu⁵, Wenlong Xiong⁶, Hui Li⁷

Affiliations

¹ Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha, 410004, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China; College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
² College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
³ Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
⁴ Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha, 410004, China.
⁵ School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China.
⁶ Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha, 410004, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China. Electronic address: xiongwenlong@zzu.edu.cn.
⁷ Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha, 410004, China. Electronic address: lihuiluoyang@163.com.

PMID: 36863149
DOI: 10.1016/j.jenvman.2023.117492

Abstract

Mobile genetic elements (MGEs) mediated horizontal gene transfer is the primary reason for the propagation of antibiotic resistance genes in environment. The behavior of MGEs under magnetic biochar pressure in sludge anaerobic digestion (AD) is still unknown. This study evaluated the effects of different dosage magnetic biochar on the MGEs in AD reactors. The results showed that the biogas yield was highest (106.68 ± 1.16 mL g^-1 VS_added) with adding optimal dosage of magnetic biochar (25 mg g^-1 TS_added), due to it increased the microorganism's abundance involved in hydrolysis and methanogenesis. While, the total absolute abundance of MGEs in the reactors with magnetic biochar addition increased by 11.58%-77.37% compared with the blank reactor. When the dosage of magnetic biochar was 12.5 mg g^-1 TS_added, the relative abundance of most MGEs was the highest. The enrichment effect on ISCR1 was the most significant, and the enrichment rate reached 158.90-214.16%. Only the intI1 abundance was reduced and the removal rates yield 14.38-40.00%, which was inversely proportional to the dosage of magnetic biochar. Co-occurrence network explored that Proteobacteria (35.64%), Firmicutes (19.80%) and Actinobacteriota (15.84%) were the main potential host of MGEs. Magnetic biochar changed MGEs abundance by affecting the potential MGEs-host community structure and abundance. Redundancy analysis and variation partitioning analysis showed that the combined effect of polysaccharides, protein and sCOD exhibited the greatest contribution (accounted for 34.08%) on MGEs variation. These findings demonstrated that magnetic biochar increases the risk of MGEs proliferation in AD system.

Keywords: Magnetic biochar; Microbial community; Mobile genetic elements; Potential host.

MeSH terms

Anaerobiosis
Anti-Bacterial Agents / pharmacology
Genes, Bacterial*
Interspersed Repetitive Sequences
Magnetic Phenomena
Manure / microbiology
Sewage*

Substances

Sewage
biochar
Anti-Bacterial Agents
Manure