Isolation and identification of cellulose-degrading endophytic bacteria from Tomoceridae (springtails)

Springtails are considered as an important candidate bioindicator to assess soil quality spiked with trace metals, but little is known of their endophytic bacteria. In this study, a kind of Tomoceridae springtail was used, and a total of 45 effective sequences were obtained through the process of endophytic bacteria isolation, culture, polymerase chain reaction (PCR) amplification and sequencing. After NCBI-BLAST, the results showed that there were 20 bacterial colonies belonging to the genus Staphylococcus, 12 belonging to the genus Bacillus, 7 belonging to the genus Paenibacillus, 1 belonging to the genus Exiguobacterium and 5 belonging to Acinetobacter lwoffii. Furthermore, five bacterial strains from these five genera (named TomoRZH14, TomoRZH26, TomoRZH30, TomoRZH37, TomoRZH40) were selected for cellulose degradation analysis. The results showed that TomoRZH26 (Bacillus sp.) seemed to have a stronger cellulose degradation ability than those of the other four strains, while the three main components cellulase endo-β-glucanase, exo-β-glucanase and β-glucosidase in TomoRZH26 showed significantly higher enzymatic activity than in the other strains. Viscosity analysis also showed that the TomoRZH26 bacterium degraded relatively quickly in cellulase fermentation medium. In general, in this study, we preliminarily revealed several endophytic bacteria of Tomoceridae springtails and found that they had potentially strong cellulose degradation activity, which may be one of the important reasons behind springtail adaptation to this kind of soil ecological environment.