Isolated strain NA16, which produces proteases, amino acids and the transcription levels of different keratinolytic enzymes and disulfide reductase genes in whole gene sequencing, was evaluated during feather degradation. The result shows under optimum fermentation conditions, chicken feather fermentation showed total amino acid concentration of 7599 mg/L, degradation efficiency of 99.3% at 72 h, and protease activity of 1058 U/mL and keratinase activity of 288 U/mL at 48 h. Goose feather fermentation showed total amino acid concentration of 4918 mg/L (96 h), and degradation efficiency was 98.9% at 120 h. Chicken feather fermentation broth at 72 h showed high levels of 17 amino acids, particularly phenylalanine (1050 ± 1.90 mg/L), valine (960 ± 1.04 mg/L), and glutamic (950 ± 3.00 mg/L). Scanning electron microscopy and Fourier transform infrared analysis revealed the essential role of peptide bond cleavage in structural changes and degradation of feathers. Protein purification and zymographic analyses revealed a key role in feather degradation of the 39-kDa protein encoded by , identified as an S8 family serine peptidase. Whole genome sequencing of NA16 revealed 26 metalloproteinase genes and 22 serine protease genes. Among the proteins, S8 family serine peptidase (, ) and S9 family peptidase () were shown by transcription analysis to play major roles in chicken feather degradation. These findings revealed the transcription levels of different families of keratinolytic enzymes in the degradation of feather keratin by microorganisms, and suggested potential applications of NA16 in feather waste management and amino acid production.

中文翻译：

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贝莱斯芽孢杆菌 NA16 菌株表现出较高的家禽羽毛降解效率、蛋白酶和氨基酸产量

分离菌株 NA16 产生蛋白酶、氨基酸，并在全基因测序中评估了不同角蛋白分解酶和二硫键还原酶基因的转录水平，并在羽毛降解过程中进行了评估。结果表明，在最佳发酵条件下，鸡毛发酵总氨基酸浓度为7599 mg/L，72 h降解效率为99.3%，48 h蛋白酶活力为1058 U/mL，角蛋白酶活力为288 U/mL。 。鹅毛发酵总氨基酸浓度为4918 mg/L（96 h），120 h降解效率为98.9%。 72 小时的鸡毛发酵液显示出高水平的 17 种氨基酸，特别是苯丙氨酸 (1050 ± 1.90 mg/L)、缬氨酸 (960 ± 1.04 mg/L) 和谷氨酸 (950 ± 3.00 mg/L)。扫描电子显微镜和傅里叶变换红外分析揭示了肽键断裂在羽毛结构变化和降解中的重要作用。蛋白质纯化和酶谱分析揭示了由 编码的 39-kDa 蛋白质在羽毛降解中的关键作用，该蛋白质被鉴定为 S8 家族丝氨酸肽酶。 NA16 的全基因组测序揭示了 26 个金属蛋白酶基因和 22 个丝氨酸蛋白酶基因。在这些蛋白质中，转录分析显示S8家族丝氨酸肽酶(,)和S9家族肽酶()在鸡羽毛降解中起主要作用。这些发现揭示了不同家族的角蛋白分解酶在微生物降解羽毛角蛋白过程中的转录水平，并表明 NA16 在羽毛废物管理和氨基酸生产中的潜在应用。