Microbial metabolism and humic acid formation in response to enhanced copper and zinc passivation during composting of wine grape pomace and pig manure

• Published in: Bioresource technology Vol. 384; p. 129226
• Main Authors: Zhang, Yingchao, Xu, Yang, Yu, Xinlong, Li, Jinkang, Chen, Guang, Wang, Shuaijie, Xu, Yanping, Xu, Rui, Zhang, Baohai, Zhang, Hongqiong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2023
• Subjects: Animals; Composting; Copper; Cu and Zn; Humic acid; Humic Substances; Manure - microbiology; Metabolic pathways; Metals, Heavy - analysis; Organic Chemicals; Passivation; Soil; Swine; Vitis; Zinc; Composting; Metabolic pathways; Humic acid; Cu and Zn; Passivation
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129226

[Display omitted] •60% and 40% WGP were optimal for Cu (47.24%) and Zn (25.82%) passivation.•S.gen_inc_sed and Cytophagales are core bacteria in the form transformation of HMs.•Amino acid and carbohydrate metabolism dominated HA production.•HA polysaccharides and aliphatic functional groups decreased Cu/Zn bioavailability.•Polyphenol conversion rate and core bacteria affected Cu/Zn chemical forms. Copper (Cu) and zinc (Zn) in piglet feed can lead to heavy metals (HMs) accumulation in pig manure (PM). Composting is crucial for recycling biowaste and decreasing HMs bioavailability. This study aimed to investigate the impact of adding wine grape pomace (WGP) on the bioavailability of HMs during PM composting. WGP facilitated the passivation of HMs through Cytophagales and Saccharibacteria_genera_incertae_sedis which promoted the formation of humic acid (HA). Polysaccharide and aliphatic groups in HA dominated the transformation of chemical forms of HMs. Moreover, adding 60% and 40% WGP enhanced the Cu and Zn passivation effects by 47.24% and 25.82%, respectively. Polyphenol conversion rate and core bacteria were identified as key factors in affecting HMs passivation. These results offered new insights into the fate of HMs during PM composting in response to the addition of WGP, which is helpful to practical application of WGP to inactivate HMs for improving compost quality.