解纤维素固氮芽孢杆菌与伴生菌的鉴定及其相互关系

Identification and interrelation of cellulose degradation nitrogen-fixing bacillus and associated bacteria

通过提高加热温度和增加稀释度分别获得解纤维素固氮芽孢杆菌与伴生菌的纯培养,依据形态特征、生理生化特性和16SrDNA序列分析对两种菌进行鉴定;将两种菌分别培养及二者按不同比例接种进行混合培养,测定活菌数量、纤维素酶活性和固氮量,探讨两种菌的相互关系。结果表明:解纤维素固氮芽孢杆菌AX32为栗树类芽孢杆菌(Paenibacillus castaneae),伴生菌AX322为根癌土壤农杆菌(Agrobacterium tumefaciens);混合培养与单独培养相比,两种菌活菌数量降低,种间关系为竞争,但混合培养时纤维素酶活性和固氮量提高。

By increasing temperature and dilution degrees,pure cultivation of cellulose degradation nitrogen-fixing bacillus and its associated strain were obtained.Based on morphological,physiological,biochemical characteristics and 16 SrDNA sequence analysis,two strains have been identified.A sole cultivation and mixed cultivation in different ratios were conducted respectively.Interrelation between two strains was discussed by determining cell count,cellulase activity and nitrogen-fixing amount.The results indicated that cellulose degradation nitrogen-fixing bacillus AX32 is Paenibacillus castaneae and its associated strain AX322 is Agrobacterium tumefaciens.Compared to the sole cultivation,viable number of both strains in mixed cultivation decreased,which suggests a competitive interspecific relationship.But both the cellulase activity and nitrogen-fixing amount increased in mixed cultivation.