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

Several strains of <i>Lysobacter</i> 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, <i>Lysobacter brunescens</i> 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 <i>L. brunescens</i> 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 <i>L. brunescens</i> YQ20 contributes to keratin degradation.