Investigating the mechanism of Zn cross-linking of chitin in a mycelium-based leather substitute and its performance evaluation.

Mycelium-based leather substitutes with a three-dimensional reticulated structure have attracted attention owing to the negative environmental impacts of natural and synthetic leather. This study utilised Ganoderma lucidum mycelium to prepare a mycelium-based leather substitute with zinc cross-linking (MF-Zn) and evaluated its physicochemical properties and sensory performance; the conventional Cr tanning method was used as reference. Results demonstrated that Zn and Cr formed cross-links with the -OH and -NHOCH groups in the polysaccharides of chitin, while Zn selectively bonded to a fraction of -NH groups in cystine and phenylalanine. The mycelium-based leather substitute with Zn cross-linking exhibited impressive tensile strength and tear strength of 7.0 MPa and 16.4 kN/m, respectively, while demonstrating desirable organoleptic properties. The free radical-scavenging capacity of MF-Zn was assessed, revealing a DPPH radical and hydroxyl radical scavenging rates of 39.4% and 52.7%, respectively. By successfully investigating the cross-linking mechanism of mycelial fibres with Zn and obtaining the stabilised mycelium-based leather substitute, this study establishes a fundamental basis for the development of sustainable leather substitutes, meeting the requirements and facilitating significant advancements in low-carbon leather substitute production.