Mechanism of feather degradation by a isolated strain Bacillus cereus C3752 and potential application in litchi preservation

Abstract

Feather waste, a protein-rich by-product of poultry industries, poses challenges in degradation and environment due to its recalcitrant nature. Microbial degradation has emerged as a promising approach, yet efficient feather-degrading microorganisms (FDMs) are still needed and the degradation mechanism remains not fully understood. In this study, we identified a FDM as Bacillus cereus (C3752). By optimizing conditions, strain C3752 achieved a feather degradation efficiency of 90.5% within 30 h. Structural analysis revealed that feather degradation likely occurred through bacterial colonization and pore formation, causing structural bifurcation and fiber reduction. Furthermore, changes in characteristic products and gene expression from strain C3752 indicated that feather degradation may include three processes: lipid hydrolysis by biosurfactants and lipases, disulfide bond disruption through efficient cysteine-based sulfite regeneration and disulfide reductases, and keratin hydrolysis. Pore formation and produced biosurfactants are reported for the first time during feather degradation. Up-regulated metabolic pathways including glycolysis, gluconeogenesis, pentose phosphate pathway, and electron transport chain likely meet energy demands for cell growth and feather degradation. The feather hydrolysates exhibited antioxidant and biosurfactant properties, showing a certain effect on post-harvest litchi preservation. These findings suggest that pore formation, cysteine-based sulfite regeneration and up-regulated metabolic pathways may be responsible for efficient feather degradation. This study provides a promising candidate and new insights into feather degradation, and opens the application of feather hydrolysates in fruit preservation.