第58届Intel ISEF中国参赛项目：对羽毛降解菌株的筛选及菌体最佳生长条件的实验探究

吉林省实验中学  高三  李昂

学科：微生物学

    本研究针对羽毛角质蛋白难以降解，造成巨大浪费这一现状。从自然界腐败羽毛中筛选出了能够有效降解角质蛋白的微生物菌株。探索出有效的筛选分离培养基和筛选菌株的方法。选择对菌株生长繁殖影响较大的因素进行了：培养基成分配比实验、培养基pH值实验、水分活度值实验、培养温度实验、培养时间实验等五个实验，找到了该菌株最佳生长条件为：蔗糖最佳加入量为羽毛粉质量的2%左右；最佳pH值7.5～8.0；水分活度值在0.95左右比较合适；最佳培养温度37℃±1℃；最佳培养时间48～52h。动物饲喂对比试验表明：经该菌株降解的角质蛋白比现有高温水解角质蛋白，动物消化率提高了34%，肉鸡增重比对照组提高了近20%，为生产羽毛蛋白饲料提供参考数据和优良菌株。

The Study of Screening of the Feather Degradation Strain and Its Best Culture Conditions

Microbiology

Li  Ang  18, Jilin Provincial Experimental School

The objective of this study was to solve the existing problem that the feather keratin is difficult to degrade, which has resulted in a big waste of protein and environmental pollution. Microbial strains that can effectively degrade the feather keratin were screened from the feather that decayed in nature. Effective isolation media and methods of screening were found out. Factors that have a larger effect on the growth and enzyme production of the strain were selected to conduct five experiments on proportioning of culture media composition, pH of culture media, water activity, culture temperature and duration. Through mensurating the numbers of thallus, nitrogen content and optical density in the degradation solution, the optimum culture conditions for the strain were found out from the experiments: cane sugar is the better carbon sources of this strains and the optimum amount of cane sugar added was approximately 2% of the weight of the feather powder, the optimum pH 7.5-8.0, the more appropriate water activity approximately 0.95, the optimum culture temperature 37℃±1℃ and the optimum culture duration 72h. The simulated experiments of the rate of pepsin digestion in animals showed that the rate of digestion in animals has reached to 70.26% after the feather keratin is degraded by the strain, and the rate of digestion in animals is increased by 34% compared with the high temperature hydrolyzed keratin now available, providing reference data and excellent strains for the production of feather protein feed.