Identification and interrelation of cellulose degradation nitrogen-fixing bacillus and associated bacteria
XIONG Ping, TAO Shuxing*, LIANG Jian, FENG Xiaolei, GUO Xian, XU Zhenzhen, TANG Na
(School of Life Sciences, Shaanxi Normal University, Xi′an 710119, Shaanxi, China)
Abstract:
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 16S rDNA 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.
KeyWords:
cellulose degradation nitrogen-fixing bacillus; associated fungus; strain identification; interrelation
