Study On The Flocculating Effect And Mechanism Of Flocculant Produced By Bacillus Mucilaginosus

This paper studied flocculating effect and flocculating mechanism of the Microbial Flocculant (MBF ) produced by a strain of Bacillus mucilaginosus BM01, which had good flocculabilities.The result of research on cultivating strain BM01 showed that the prime culture period of strain BM01 producing MBF was 5 days; We educed the conclusion that the flocculating active component should be metabolites of the strain but not bacterial cell; The result of determining the distribution of flocculating activities in culture indicated that the flocculating activities content of Bacteria—mineral composition was higher than that of supernatant culture slightly.Single factor experiment and orthogonal experiment were studied on the culture conditions of stain BM01 producing flocculant, and the results suggested that sucrose was used as carbon sourse which the content of was 5‰ ,and the content of the clay mineral poweder was 2.5‰. In addition, the flocculating rate of MBF-BM01 arrived at 95.2% at pH7 of medium, when we disposed of 3‰ Kaolin clay suspension liquid.The results were showed by single factor experiment and orthogonal experiment researcheded on the optimal condition of MBF-BM01 treating with domestic waste water as follows: flocculant addition was 6mL/100mL waste water, pH value of flocculating system was 9 and the flocculating time was 6 hours. In the conditions stated hereinbefore, MBF-BM01 can get a highest flocculating rate 94.24%.We detected the biomacromolecule extracted from MBF-BM01 by UV , IR testing means and so on, and the results were showed as follows: the major effective components of MBF-BM01 were acidic polysaccharide, which were of an anionic flocculant; Reaseach model of Bacillus mucilaginosus flocculating mechanism was studied by MBF-BM01 effecting on Kaolin, furthermore, the inspection of particle-size distribution in flocculating system and the observation by TEM indicated that the flocculation molecule and kaolin microparticle could flocculate by "bridge", finally deposited. The process can be described roughly: at the beginning of flocculation, the Van der Waals force overcame the electrostatic repulsion that occured between the same kind of charge, and caused the biomacromolecular of MBF-BM01 and the kaolin microparticle to close up; along with the abridgement of...