角蛋白降解菌分离、鉴定及其降解机制研究  

Research on isolation and identification of keratin-degrading bacterias and its degradation mechanism

作　　者：齐志国[1] 张铁鹰[1] 董杰丽[1] 杜家菊[2] 

机构地区：[1]中国农业科学院北京畜牧兽医研究所动物营养学国家重点实验室,北京100193 [2]山东理工大学生命科学学院,山东淄博255049

出　　处：《饲料工业》2012年第17期19-24,共6页Feed Industry

基　　金：农业部948项目资助"特种蛋白水解酶的引进;优化和创新应用研究"[2010-Z4]

摘　　要：实验旨在筛选具有高效角蛋白水解活性的微生物,并对其降解羽毛角蛋白机制进行研究,为提高角蛋白生物降解率提供理论指导。采用透明圈和完整羽毛降解相结合的方法,从废弃羽毛中筛选角蛋白降解菌,并进一步研究其羽毛角蛋白降解过程。获得一株可高效降解角蛋白菌株,基于形态观察和16S rDNA分子鉴定,该菌被命名为Bacillus licheniformis CP-7,其5 d可将天然完整羽毛完全降解。CP-7发酵过程产生大量巯基、可溶性蛋白和亚硫酸盐。分离发酵48 h菌株胞内、胞外粗酶液,发现胞外酶液具有较高的角蛋白酶活性,而胞内酶液具有一定二硫键还原酶活性。胞内酶液能够极显著地促进胞外酶液水解角蛋白活性(P<0.01),但对酪蛋白水解活性无影响(P>0.05)。筛选菌CP-7为具有高二硫键还原能力的角蛋白降解菌,二硫键还原酶可能是高效降解羽毛角蛋白的关键。This study aimed at screening of the microorganisms with high keratinolytic activity and providing a theoretical basis to investigate the mechanism of degradation of feather keratin and improve the utilization of keratin resources. In this work, we isolated keratin-degrading microorganisms from decomposed feathers by combining the method of clearance zone diameter and complete feather degradation, furtherly, analyzed the feather keratin degradation process. After observing the shape feature and sequeneing the 16S rDNA, Strain CP-7 was identified and named as Bacillus licheniformis CP-7, which could completely degrade natural feathers during five days. The liquid fermentation results showed much thiol and soluble protein and sulfite were produced during the fermentation process. Studying the intracellular and extracellular crude enzyme（fermentation 48 h） found that extracellular enzyme and intracel- lular enzyme had high keratinase activity and disulfide reductase activity, respectively. Intracellular enzyme could significantly promote the extracellular keratinase activity （P〈0.01）, but no effect on the caseinolytic activity. Therefore, Bacillus licheniformis CP-7 is a keratin-degrading bacterium with high disulfide bond-reducing capacity, when disulfide reductase plays an important role in the microbial keratin-degrading.

关 键 词：角蛋白降解菌 巯基 角蛋白酶 二硫键还原酶 

分 类 号：S816.48[农业科学—饲料科学]