ABSTRACT

Keratinous biomass valorization for value-added products presents a high prospect in ecological management and the advancement of the bio-economy. Consequently, soil samples from the poultry dumpsite were collected. The bacteria isolated on the basal salt medium were screened for keratinolytic activity. The potent chicken feathers degrading bacteria were identified through 16S rRNA gene sequencing and phylogenetic analysis. Fermentation process conditions were optimized, and the amino acid compositions of the feather hydrolysate were likewise quantified. Ten (10) proteolytic bacteria evaluated on skimmed milk agar showed intact chicken feather degradation ranging from 33% (WDS-03) to 88% (FPS-09). The extracellular keratinase activity ranged from 224.52 ± 42.46 U/mL (WDS-03) to 834.55 ± 66.86 U/mL (FPS-07). Based on 16S rRNA gene sequencing and phylogenetic analysis, the most potent keratinolytic isolates coded as FPS-07, FPS-09, FPS-01, and WDS-06 were identified as Chryseobacterium aquifrigidense FANN1, Chryseobacterium aquifrigidense FANN2, Stenotrophomonas maltophilia ANNb, and Bacillus sp. ANNa, respectively. C aquifrigidense FANN2 maximally produced keratinase (1460.90 ± 26.99 U/mL) at 72 h of incubation under optimal process conditions of pH (6), inoculum side (5%; v/v), temperature (30°C), and chicken feather (25 g/L). The feather hydrolysate showed a protein value of 67.54%, with a relative abundance of arginine (2.84%), serine (3.14%), aspartic acid (3.33%), glutamic acid (3.73%), and glycine (2.81%). C. aquifrigidense FANN2 yielded high keratinase titre and dismembered chicken feathers into amino acids-rich hydrolysate, highlighting its significance in the beneficiation of recalcitrant keratinous wastes into dietary proteins as potential livestock feed supplements.

摘要

增值产品的角质生物质增值在生态管理和生物经济的发展方面具有很高的前景。因此，收集了家禽垃圾场的土壤样本。筛选在基础盐培养基上分离的细菌的角质溶解活性。通过 16S rRNA 基因测序和系统发育分析鉴定出有效的鸡毛降解菌。优化了发酵工艺条件，同样对羽毛水解物的氨基酸组成进行了量化。在脱脂牛奶琼脂上评估的十 (10) 种蛋白水解细菌显示完整的鸡羽毛降解范围为 33% (WDS-03) 至 88% (FPS-09)。细胞外角蛋白酶活性范围从 224.52 ± 42.46 U/mL (WDS-03) 到 834.55 ± 66.86 U/mL (FPS-07)。Chryseobacterium aquifrigidense FANN1、Chryseobacterium aquifrigidense FANN2、Stenotrophomonas maltophilia ANNb 和Bacillus sp。分别是安娜。在 pH (6)、接种侧 (5%; v/v)、温度 (30°C) 和鸡毛的最佳工艺条件下，C aquifrigidense FANN2 在孵育 72 小时时最大程度地产生角蛋白酶 (1460.90 ± 26.99 U/mL) （25 克/升）。羽毛水解物的蛋白质值为 67.54%，其中精氨酸 (2.84%)、丝氨酸 (3.14%)、天冬氨酸 (3.33%)、谷氨酸 (3.73%) 和甘氨酸 (2.81%) 的相对丰度较高。C. aquifrigidenseFANN2 产生高角蛋白酶滴度并将鸡羽毛分解成富含氨基酸的水解产物，突出了其在将顽固角质废物选矿为膳食蛋白质作为潜在牲畜饲料补充剂方面的重要性。