Gurav Ranjit G, Tang Jingchun, Jadhav Jyoti P
Department of Biotechnology, Shivaji University, Kolhapur, 416004, India.
College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China.
3 Biotech. 2016 Dec;6(2):145. doi: 10.1007/s13205-016-0464-0. Epub 2016 Jun 23.
In black feathers, melanin is embedded in keratin matrix that makes feather more resistance to the microbial degradation. Chryseobacterium sp. RBT previously isolated from the poultry waste disposable site revealed strong sulfitolytic and keratinolytic activities. Maximum keratinase activity was observed at 48 h (89.12 U ml) showed 83 % of native black feather degradation. The concentration of free sulfhydryl groups released during degradation was 0.648 × 10 M (12 h), 2.144 × 10 M (96 h), and however, declined on prolong incubation to 1.752 × 10 M (120 h). Melanin was released in the degradation medium after microbial exploitation of black feather. After purification, melanin was dark brown colored powder insoluble in water, 5 M HCL, ethanol, methanol, benzene, chloroform, and acetone; whereas, soluble in KOH and NaOH. On exposure to oxidizing and reducing reagents feather melanin showed decolorization, while formed a brown precipitate when reacted with FeCl. The spectroscopic characterization of isolated melanin demonstrated absorption at infra-red region. Similarly, UV-visible scan confirmed that increase in the wavelength progressively declined the absorbance of pigment. The crude keratinase enzyme (2 % v/v) produced during degradation showed complete dehairing of goat skin within 20 h.
在黑色羽毛中，黑色素嵌入角蛋白基质中，使羽毛更能抵抗微生物降解。先前从家禽粪便处理场分离出的 Chryseobacterium sp. RBT 显示出强大的亚硫酸分解和角蛋白分解活性。在48小时观察到最大角蛋白酶活性（89.12 U/ml），显示出83%的天然黑色羽毛降解。降解过程中释放的游离巯基浓度在12小时为0.648×10 M，96小时为2.144×10 M，然而，延长孵育至120小时后降至1.752×10 M。黑色羽毛经微生物利用后，黑色素释放到降解培养基中。纯化后，黑色素为深棕色粉末，不溶于水、5 M盐酸、乙醇、甲醇、苯、氯仿和丙酮；而可溶于氢氧化钾和氢氧化钠。暴露于氧化和还原试剂时，羽毛黑色素会脱色，与氯化铁反应时会形成棕色沉淀。分离出的黑色素的光谱表征显示在红外区域有吸收。同样，紫外可见扫描证实，随着波长增加，色素的吸光度逐渐下降。降解过程中产生的粗角蛋白酶（2% v/v）在20小时内使山羊皮完全脱毛。
