Biodegradation of chicken feathers under oxygen-limited conditions: An alternative approach for nutrient recovery from feather waste

Poultry feathers are a challenging-to-degrade solid waste that requires proper management and treatment technologies. Conventionally, feather waste is treated by composting, which requires oxygen and takes a long time. Here, we present a method for degrading feather waste under oxygen-limited conditions, shortening the treatment time to 8 weeks while achieving a high decomposition efficiency of 81 %. The emission of sulfide odor was controlled as the degradation process was performed in closed chambers without aeration. The process produced feather lysate at a high yield of 0.9 L kg⁻¹, retaining most of the nutrients from the feather waste. No PAHs, heavy metals, or pathogens were detected in the feather lysate, indicating a low risk for agricultural use. Feather lysate with a high keratinase content of 1330.13 U mL⁻¹ can be a source for obtaining this enzyme for various applications. The bacterial genera Keratinibaculum and Bacillus were identified as key drivers of the feather decomposition process.