Chromium-Tanned Leather and Microbial Consortia: Identification of Taxa With Biodegradation Potential and Chromium Tolerance.

Chromium-tanned leather waste poses significant environmental challenges due to its resistance to degradation and heavy metal content. This study investigates the potential of naturally selected microbial consortia to initiate the degradation of chromium-tanned leather and identifies key bacterial genera capable of tolerating chromium and producing enzymes relevant to collagen breakdown. A novel multidisciplinary approach combining gravimetric assays, metagenomic sequencing, and scanning electron microscopy (SEM) was applied to characterise both microbial composition and degradation dynamics. Dominant genera such as Bacillus, Microbacterium, and Acinetobacter were associated with collagen degradation and metal tolerance, with Bacillus-rich communities showing the most pronounced mass loss (up to 3%). SEM analysis revealed the formation of robust biofilms and extensive matrix disruption, indicating enzymatic activity and structural breakdown of the leather. The formation of exopolysaccharide-rich biofilms was found to be critical for microbial adhesion and biodegradation efficacy. These findings provide initial insights into microbial mechanisms involved in the degradation of chromium-tanned leather and suggest potential applications for microbial consortia in future sustainable leather waste management strategies.