一株产角蛋白酶的铜绿假单胞菌的分离鉴定

本研究从鸡场长期堆放羽毛的土壤中筛选到一株降解羽毛能力强的菌株。该菌株在牛奶平板上培养24 h后产生透明降解圈，形状不规则，表面粗糙，边缘模糊，产生绿色荧光色素；革兰氏染色阴性，短杆状，无芽孢，有鞭毛，无荚膜。生化试验显示，该分离株能够水解牛奶、明胶，具有角蛋白酶活性，能利用柠檬酸盐，硝酸还原反应阳性。系统进化树分析显示，分离株与铜绿假单胞菌模式菌株（GenBank登录号：BAMA01000316）亲缘关系最近，综合以上结果，最终确定分离株为铜绿假单胞菌，并正式命名为Pesudomonas aeruginosa B1-2。将该分离株在以1%羽毛为唯一碳氮源的基础培养基中发酵培养，48 h后角蛋白酶活性最高达到60.3 U/mL，对羽毛降解率为85.7%。本研究中分离获得的Pesudomonas aeruginosa B1-2可用于畜禽废弃物的处理。

Isolation and Identification of A Keratinase-producing Strain of Pseudomonas aeruginosa B1-2

A new feather-degrading bacterium was isolated from soil samples colected from pile-up feather places in this study.The transparent circle was produced after the strain was cultured on the milk medium for 24 h,the colony shape of the strain was irregular,rough surface,edge blur,and could produce green fluorescent pigment.It was gram negative,short rod,nospore and capsule and had a flagellum scanning by electron microscope. Biochemical test showed that the isolate could hydrolyze milk and gelatin,utilize citrate with keratinase activity and nitrate reduction reaction positive.Phylogenetic tree analysis showed that the isolate was most closely related to Pseudomonas aeruginosa strain (GenBank accession No.:BAMA01000316).Combined with the above results,the isolated strain was identified as Pseudomonas aeruginosa B1-2. When it was inoculated on basal medium containing 1% feather as sole carbon and nitrogen source,the highest level of keratinase activity was 60.3 U/mL after 48 h while the degradation rate of feather was 85.7%. This result indicated that the newly isolated Pseudomonas aeruginosa B1-2 could be useful in management of farm wastes.