# Integrated Transcriptomic and Proteomic Analyses Uncover the Mechanisms of Keratin Degradation in Lysobacter brunescens YQ20

## TL;DR

This study identifies the molecular mechanisms used by Lysobacter brunescens YQ20 to efficiently degrade wool, offering insights for biodegradation technologies.

## Contribution

The study reveals specific metabolic pathways and keratinase families involved in keratin degradation by L. brunescens YQ20.

## Key findings

- Highly active amino acid biosynthesis and sulfur metabolism pathways support keratin degradation.
- Keratinases from S8, M14, and M28 families synergistically hydrolyze keratin.
- Upregulated sulfur metabolism genes help cleave disulfide bonds in keratin.

## Abstract

Lysobacter brunescens YQ20 exhibits highly efficient wool degradation capabilities. In this study, transcriptomic and proteomic analyses were conducted to elucidate the underlying mechanisms of keratin degradation. The results showed that amino acid biosynthesis, sulfur metabolism, and keratinase production contribute to efficient wool degradation. Our results provide a theoretical basis for the biodegradation technology for wool waste, contributing to the resource utilization of textile waste.

Several strains of Lysobacter have demonstrated keratin-degrading capabilities, positioning them as promising candidates for the degradation and utilization of wool waste. In our previous study, a novel strain, Lysobacter brunescens YQ20, exhibiting highly efficient keratin degradation capabilities, was isolated. In this study, transcriptomic and proteomic analyses were conducted to elucidate the underlying mechanisms of keratin degradation. Our findings revealed that several metabolic pathways, specifically, valine, leucine, and isoleucine biosynthesis; phenylalanine, tyrosine, and tryptophan biosynthesis; glycine, serine, and threonine metabolism; and histidine metabolism, were highly active during keratin degradation, thereby supporting the growth and metabolism of L. brunescens YQ20. Additionally, the upregulation of genes related to sulfur metabolism, cysteine and methionine metabolism, and glutathione metabolism pathways facilitated the cleavage of disulfide bonds in keratin. Moreover, keratinases identified among the differentially expressed genes and proteins (DEGs/DEPs) were classified into the S8, M14, and M28 families, whose synergistic activity contributed to the efficient hydrolysis of keratin. Collectively, these results provide valuable insights into the molecular mechanisms by which L. brunescens YQ20 contributes to keratin degradation.