Insight into the fraction variations of selenium and their effects on humification during composting

• Published in: Bioresource technology 2022-11, Vol.364, p.128050, Article 128050
• Main Authors: Wang, Zhaoyu, Zhao, Mengxiang, Xie, Jianwen, Wang, Zhen, Tsui, To-Hung, Ren, Xiuna, Zhang, Zengqiang, Wang, Quan
• Format: Article
• Language: English
• Subjects: CAZymes genes; Composting; Humification; Selenium; Selenium fractions
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2022.128050

[Display omitted] •Selenate added treatment had more SOL-Se and EXC-Se than selenite added treatment.•Selenium promoted the compost humification, especially selenite.•Selenite and selenate enhanced the different key bacteria in humus transformation.•Selenium increased the genes encoding carbohydrate-active enzymes. This study investigated the variation of selenium fractions and their effects on humification during composting. Selenite and selenate were added to a mixture of goat manure and wheat straw for composting. The results demonstrated that the bioavailable Se in the selenite added treatment (9.3–13.8%) was lower than in the selenate added treatment (18.1–47.3%). Meanwhile, the HA/FA of selenite and selenate added treatments were higher than in control, indicating that the selenium addition (especially selenite) promoted the humification of composting. Importantly, selenite enriched the abundance of Tepidimicrobium and Virgibacillus which were responsible to improve humification performance. Selenate increased the abundance of Thermobifida and Cellvibrio which facilitated the composting humification. The genes encoding CAZymes involved in the degradation of organic materials were also analyzed, and selenium could contribute to the synthesis of humus. KEGG pathway analysis revealed that the selenite addition promoted amino acids and carbohydrate metabolism compared to the control.