Effect of sediment extract on the culturable aerobic bacterial diversity in the sediments of Taihu Lake

Abstract:

[Objective] The study is aimed to research the effect of adding sediment extract or not on the cultivable bacterial diversity in the sediment of Taihu Lake. [Methods] By using R2A medium and sediment extract R2A medium to isolate and culture the bacteria in the sediment. Phylogenetic analysis based on the 16S rRNA gene was used to identify the bacterial diversity. [Results] Results showed that the amount of the bacteria cultured on sediment extract R2A increased up to 1.6 times more than that of on R2A medium. Analysis based on the similarities of 16S rRNA gene sequences of isolates presented effects on the dominant bacteria. On the R2A medium, the dominant bacterial groups were Firmicutes (52%), Actinobacteria (24%), Proteobacteria (20%) and Bacteroidetes (4%), and most of the bacteria isolated from R2A were closely related to genera Bacillus, Pseudomonas and Archrobacter. However, the dominant bacterial groups isolated from sediment extract R2A were Proteobacteria (40%), Actinobacteria (35%), Firmicutes (22.5%), and Bacteroidetes (2.5%). They are closely related to Sphingomonas, Bacillus, Paracoccus and Arthrobacter. [Conclusion] Adding the original nutrient factors of the sediment extract could increase the diversity of bacteria in the sediment and help to increase the cultivable efficiency.