On Optimization Study of Cultivation Conditions of a Flocculant-Producing Strain and 16s rDNA-Sequential Analysis

The article introduces the authors´research of an optimum method on the cultivation conditions of a flocculant- producing Strain. Using single factor experiments and orthogonal test, the influence of temperature, PH value and rotational speed on synthesis of microbial flocculants, and optimized culture conditions were studied; 16S gene of the strain was amplified and sequenced.The sequencing was BLAST search in Genebank and phylogenetic tree was constructied to make certain the taxonomic status of the strain. The results: the optimum culture conditions of the flocculant-producing strain to produce microbial flocculants were 28degC, initial pH 8, 160r/min; The effects of other factors needs further study. The 16S gene sequence of the strain had the high homology to Bacillus megaterium(>99%), the phylogenetic tree also showed that the strain and Bacillus megaterium were in the same branch. We could draw a conclusion that the microbial flocculants producing strain was identified as Bacillus megaterium.