Novel ferrous disulfide loaded palygorskite composites as additives in lignocellulosic waste composting for improving humification

Abstract

Improving the composting efficiency of lignocellulose wastes has been the focus in the field of aerobic fermentation. In this study, FeS2 was modified on the surface of palygorskite to regulate the straw composting. Material characterizations showed that FeS2/Pal composite exhibited glutathione oxidase and catalase activities, attributing to the fact that nano FeS2 filled the aggregation space of the original palygorskite, exposing more active sulfur vacancy defects. During the composting process, the addition of FeS2/Pal could adjust pH value and increase electrical conductivity, which was conducive to improving the efficiency of biological redox process. The total degradation ratio of cellulose was 52.54% with FeS2/Pal added. The repolymerization of small molecule intermediates was strengthened, and the final polymerization degree and maturity of composting products was improved. Since the sequence abundance of aromatic amino acids biosynthesis and carbon fixation pathways was higher revealed by PICRUSt. High-throughput sequencing results showed that bacterial community was more dominant than fungi, with community richness index increased by 2.3–3.7 times. The pathogenic bacteria such as Atopostipes and Corynebacterium were disappeared, and heat-resistant bacteria were dominant. The key bacteria and fungi in the group added with FeS2/Pal were Limnochordaceae and Melanocarpus genus, which were related to the cellulose enzymatic hydrolysis and humification degree.