Soil burial evaluation of finished leather biodegradability: microbial community dynamics and biogeochemical cycles

Abstract

Biodegradability of finished leather is crucial for the sustainable development of the leather industry. Herein, the biodegradability evaluation system of finished leather was engineered using soil burial degradation, microbial community dynamics, and biogeochemical cycles. The protein content of chrome grain leather (CGL), chrome-free grain leather (FGL) and chrome-free suede leather (FSL) exceeded 60%, indicating their inherent biodegradation potential during soil burial. After 6 months of soil burial, the biodegradation rate of FGL was around 2.16-fold that of CGL, demonstrating higher biodegradability of chrome-free finished leather. Besides, total nitrogen contents in FSL and CGL soils at 9 months were 2.45- and 1.07- fold those in the initial soil, respectively. These results suggested that organic matter from the finished leathers, particularly chrome-free finished leathers, was gradually released during soil burial degradation. Metagenome sequencing revealed that the diversity of the soil microbial community was considerably enhanced by the soil burial degradation of finished leather. Pseudomonadota, Actinomycetota, and Chloroflexota are the dominant bacteria phyla driving the soil burial biodegradation of finished leather. Accordingly, the degradation of finished leather can change the relative abundance of genes encoding enzymes involved in amino acid metabolism. The degradation of finished leather may continuously release nitrogen-containing substrates, supporting key nitrogen cycling processes including organic nitrogen metabolism, nitrification, assimilation, and nitrate reduction. These results diversify the evaluation systems for finished leather biodegradability, and demonstrate that chrome-free finished leather holds significant promise for the sustainable development of the leather industry.

Graphical abstract

Keywords

Finished leather / Biodegradation / Soil burial / Metagenome / Microbial community / Biogeochemical cycle

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Funding

Jing-Jin-Ji Regional Integrated Environmental Improvement-National Science and Technology Major Project(2025ZD1203500)

Fundamental Research Funds for the Central Universities(Fundamental Research Funds for the Central Universities)

RIGHTS & PERMISSIONS

The Author(s)